diff --git a/docs/rules/template-require-iframe-title.md b/docs/rules/template-require-iframe-title.md
index 145f9bd4ec..a3dc0d06ad 100644
--- a/docs/rules/template-require-iframe-title.md
+++ b/docs/rules/template-require-iframe-title.md
@@ -6,9 +6,11 @@
 
 ## `<iframe>`
 
-`<iframe>` elements must have a unique title property to indicate its content to the user.
-
-This rule takes no arguments.
+`<iframe>` elements must have a unique title property so assistive
+technology can convey their content to the user. The normative
+requirement is [WCAG SC 4.1.2 (Name, Role, Value)](https://www.w3.org/TR/UNDERSTANDING-WCAG20/ensure-compat-rsv.html);
+the `title` attribute is _one sufficient technique_ for meeting it
+(sufficient technique [H64](https://www.w3.org/WAI/WCAG21/Techniques/html/H64)).
 
 ## Examples
 
@@ -27,12 +29,40 @@ This rule **forbids** the following:
 <template>
   <iframe />
   <iframe title='' />
+  <iframe title='   ' />
+  <iframe title={{null}} />
+  <iframe title={{undefined}} />
+  <iframe title={{42}} />
 </template>
 ```
 
+Whitespace-only `title` (`"   "`) is flagged by default as an
+authoring-hygiene check: HTML and ACCNAME technically permit it (step 2I
+doesn't trim), but a whitespace-only accessible name is useless in
+practice. Suppress this specific strictness via
+`allowWhitespaceOnlyTitle: true` if your codebase needs it.
+
+## Configuration
+
+- `allowWhitespaceOnlyTitle` (`boolean`, default `false`): when `true`,
+  `<iframe title="   ">` is accepted. Empty-string `title=""` and
+  non-string mustache literals (`{{null}}`, `{{undefined}}`, `{{42}}`) are
+  still flagged.
+
+```js
+module.exports = {
+  rules: {
+    'ember/template-require-iframe-title': ['error', { allowWhitespaceOnlyTitle: true }],
+  },
+};
+```
+
 ## References
 
-- [Deque University](https://dequeuniversity.com/rules/axe/1.1/frame-title)
-- [Technique H65: Using the title attribute of the frame and iframe elements](https://www.w3.org/TR/2014/NOTE-WCAG20-TECHS-20140408/H64)
-- [WCAG Success Criterion 2.4.1 - Bypass Blocks](https://www.w3.org/TR/UNDERSTANDING-WCAG20/navigation-mechanisms-skip.html)
-- [WCAG Success Criterion 4.1.2 - Name, Role, Value](https://www.w3.org/TR/UNDERSTANDING-WCAG20/ensure-compat-rsv.html)
+- [WCAG SC 4.1.2 — Name, Role, Value](https://www.w3.org/TR/UNDERSTANDING-WCAG20/ensure-compat-rsv.html)
+  — the normative requirement.
+- [WCAG Technique H64 — Using the title attribute of the iframe element](https://www.w3.org/WAI/WCAG21/Techniques/html/H64)
+  — a sufficient technique for SC 4.1.2, not itself normative.
+- [WCAG Success Criterion 2.4.1 — Bypass Blocks](https://www.w3.org/TR/UNDERSTANDING-WCAG20/navigation-mechanisms-skip.html)
+- [ACCNAME 1.2 — accessible-name computation](https://www.w3.org/TR/accname-1.2/)
+- [axe-core rule `frame-title`](https://dequeuniversity.com/rules/axe/4.10/frame-title)
diff --git a/lib/rules/template-require-iframe-title.js b/lib/rules/template-require-iframe-title.js
index d4f4b2f636..ced7166548 100644
--- a/lib/rules/template-require-iframe-title.js
+++ b/lib/rules/template-require-iframe-title.js
@@ -1,3 +1,43 @@
+'use strict';
+
+// Non-string literal AST nodes (boolean/null/undefined/number) don't represent
+// a meaningful author-provided title. Even though they would coerce to strings
+// at runtime (e.g. `true` → "true", `42` → "42"), those strings do not describe
+// the frame's content — the rule rejects the literal forms.
+const INVALID_LITERAL_TYPES = new Set([
+  'GlimmerBooleanLiteral',
+  'GlimmerNullLiteral',
+  'GlimmerUndefinedLiteral',
+  'GlimmerNumberLiteral',
+]);
+
+function isInvalidTitleLiteralPath(path) {
+  return INVALID_LITERAL_TYPES.has(path?.type);
+}
+
+function getInvalidLiteralType(path) {
+  if (!path) {
+    return undefined;
+  }
+  switch (path.type) {
+    case 'GlimmerBooleanLiteral': {
+      return 'boolean';
+    }
+    case 'GlimmerNullLiteral': {
+      return 'null';
+    }
+    case 'GlimmerUndefinedLiteral': {
+      return 'undefined';
+    }
+    case 'GlimmerNumberLiteral': {
+      return 'number';
+    }
+    default: {
+      return undefined;
+    }
+  }
+}
+
 /** @type {import('eslint').Rule.RuleModule} */
 module.exports = {
   meta: {
@@ -8,13 +48,24 @@ module.exports = {
       url: 'https://github.com/ember-cli/eslint-plugin-ember/tree/master/docs/rules/template-require-iframe-title.md',
       templateMode: 'both',
     },
-    schema: [],
+    schema: [
+      {
+        type: 'object',
+        properties: {
+          allowWhitespaceOnlyTitle: {
+            type: 'boolean',
+          },
+        },
+        additionalProperties: false,
+      },
+    ],
     messages: {
-      // Four messageIds (missingTitle, emptyTitle, dynamicFalseTitle,
-      // duplicateTitle) for richer diagnostic detail.
+      // Five messageIds (missingTitle, emptyTitle, invalidTitleLiteral,
+      // duplicateTitleFirst, duplicateTitleOther) for richer diagnostic detail.
       missingTitle: '<iframe> elements must have a unique title property.',
       emptyTitle: '<iframe> elements must have a unique title property.',
-      dynamicFalseTitle: '<iframe> elements must have a unique title property.',
+      invalidTitleLiteral:
+        '<iframe title> must be a non-empty string. Got a {{literalType}} literal, which does not describe the frame contents.',
       duplicateTitleFirst: 'This title is not unique. #{{index}}',
       duplicateTitleOther:
         '<iframe> elements must have a unique title property. Value title="{{title}}" already used for different iframe. #{{index}}',
@@ -27,6 +78,14 @@ module.exports = {
     },
   },
   create(context) {
+    // Whitespace-only `title="   "` is technically spec-compliant: ACCNAME
+    // 1.2 step 2I (Tooltip) does not whitespace-trim like step 2D
+    // (aria-label) does, so a 3-space accessible name is assigned. That is
+    // useless in practice but not a spec violation. Default behavior flags
+    // it as authoring hygiene; set `allowWhitespaceOnlyTitle: true` to
+    // align with spec/peer behavior.
+    const allowWhitespaceOnlyTitle = Boolean(context.options[0]?.allowWhitespaceOnlyTitle);
+
     // Each entry: { value, node, index }
     //  - value: trimmed title string
     //  - node: original element node for the first occurrence
@@ -57,9 +116,15 @@ module.exports = {
         if (titleAttr.value) {
           switch (titleAttr.value.type) {
             case 'GlimmerTextNode': {
-              const value = titleAttr.value.chars.trim();
+              const raw = titleAttr.value.chars;
+              const value = raw.trim();
               if (value.length === 0) {
-                context.report({ node, messageId: 'emptyTitle' });
+                // Empty-string title always fails: no accessible name for screen readers.
+                // Whitespace-only titles are controlled by the `allowWhitespaceOnlyTitle`
+                // option (default false).
+                if (raw.length === 0 || !allowWhitespaceOnlyTitle) {
+                  context.report({ node, messageId: 'emptyTitle' });
+                }
               } else {
                 // Check for duplicate titles. Reports BOTH the first and the
                 // current occurrence on every collision, sharing a `#N` index
@@ -93,21 +158,31 @@ module.exports = {
               break;
             }
             case 'GlimmerMustacheStatement': {
-              // title={{false}} → BooleanLiteral false is invalid
-              if (titleAttr.value.path?.type === 'GlimmerBooleanLiteral') {
-                context.report({ node, messageId: 'dynamicFalseTitle' });
+              // title={{false}} / title={{null}} / title={{undefined}} / title={{42}}
+              // — any literal that doesn't produce a meaningful accessible name.
+              if (isInvalidTitleLiteralPath(titleAttr.value.path)) {
+                context.report({
+                  node,
+                  messageId: 'invalidTitleLiteral',
+                  data: { literalType: getInvalidLiteralType(titleAttr.value.path) },
+                });
               }
               break;
             }
             case 'GlimmerConcatStatement': {
-              // title="{{false}}" → ConcatStatement with single BooleanLiteral part
+              // title="{{false}}" / "{{undefined}}" / etc. — ConcatStatement
+              // with a single literal part that doesn't produce a name.
               const parts = titleAttr.value.parts || [];
               if (
                 parts.length === 1 &&
                 parts[0].type === 'GlimmerMustacheStatement' &&
-                parts[0].path?.type === 'GlimmerBooleanLiteral'
+                isInvalidTitleLiteralPath(parts[0].path)
               ) {
-                context.report({ node, messageId: 'dynamicFalseTitle' });
+                context.report({
+                  node,
+                  messageId: 'invalidTitleLiteral',
+                  data: { literalType: getInvalidLiteralType(parts[0].path) },
+                });
               }
               break;
             }
diff --git a/tests/audit/iframe-title/peer-parity.js b/tests/audit/iframe-title/peer-parity.js
new file mode 100644
index 0000000000..f7c8584182
--- /dev/null
+++ b/tests/audit/iframe-title/peer-parity.js
@@ -0,0 +1,217 @@
+// Audit fixture — translates peer-plugin test cases into assertions against
+// our rule (`ember/template-require-iframe-title`). Runs as part of the
+// default Vitest suite (via the `tests/**/*.js` include glob) and serves
+// double-duty: (1) auditable record of peer-parity divergences,
+// (2) regression coverage pinning CURRENT behavior. Each case encodes what
+// OUR rule does today; divergences from upstream plugins are annotated as
+// `DIVERGENCE —`. Peer-only constructs that can't be translated to Ember
+// templates (JSX spread props, Vue v-bind, Angular `$event`, undefined-handler
+// expression analysis) are marked `AUDIT-SKIP`.
+//
+// Peers covered: jsx-a11y/iframe-has-title,
+// vuejs-accessibility/iframe-has-title, lit-a11y/iframe-title.
+//
+// Source files (context/ checkouts):
+//   - eslint-plugin-jsx-a11y-main/__tests__/src/rules/iframe-has-title-test.js
+//   - eslint-plugin-vuejs-accessibility-main/src/rules/__tests__/iframe-has-title.test.ts
+//   - eslint-plugin-lit-a11y/tests/lib/rules/iframe-title.js
+
+'use strict';
+
+const rule = require('../../../lib/rules/template-require-iframe-title');
+const RuleTester = require('eslint').RuleTester;
+
+const ruleTester = new RuleTester({
+  parser: require.resolve('ember-eslint-parser'),
+  parserOptions: { ecmaVersion: 2022, sourceType: 'module' },
+});
+
+ruleTester.run('audit:iframe-title (gts)', rule, {
+  valid: [
+    // === Upstream parity — basic cases ===
+    // jsx-a11y / vue-a11y / lit-a11y: valid (no iframe, or titled iframe).
+    '<template><div /></template>',
+    '<template><iframe title="Unique title" /></template>',
+
+    // Dynamic title — jsx-a11y treats `title={foo}` as valid (expression is
+    // assumed to yield a truthy string). vue-a11y: valid for `:title="foo"`.
+    // lit-a11y: valid for `title=${foo}`. Ours: valid for `{{someValue}}`.
+    '<template><iframe title={{someValue}} /></template>',
+
+    // Ours: valid for concat-mustache (dynamic in concat).
+    // No direct jsx-a11y analogue because JSX has no string-interpolation; but
+    // the equivalent `title={`${foo}`}` is treated as valid by jsx-a11y.
+    '<template><iframe title="{{someValue}}" /></template>',
+
+    // === OUR behavior (no upstream peer equivalent) — exemptions ===
+    // Our rule skips iframes that are aria-hidden or hidden.
+    //   - jsx-a11y: does NOT exempt aria-hidden; `<iframe aria-hidden />`
+    //     without a title is still flagged.
+    //   - vue-a11y / lit-a11y: same — no aria-hidden/hidden exemption.
+    // Intentional: matches ember-template-lint upstream behavior.
+    '<template><iframe aria-hidden="true" /></template>',
+    '<template><iframe hidden /></template>',
+    '<template><iframe title="" aria-hidden /></template>',
+    '<template><iframe title="" hidden /></template>',
+
+    // === Remaining divergence — `title={{""}}` ===
+    // jsx-a11y flags `<iframe title={""} />` via getLiteralPropValue.
+    // Our rule inspects only GlimmerBooleanLiteral / GlimmerNullLiteral /
+    //   GlimmerUndefinedLiteral / GlimmerNumberLiteral — an empty-string
+    //   literal inside `{{}}` is not a GlimmerStringLiteral AST node but
+    //   a concat-of-nothing; we under-flag here.
+    '<template><iframe title={{""}} /></template>',
+
+    // === Disambiguation — distinct titles across iframes (all valid) ===
+    '<template><iframe title="foo" /><iframe title="bar" /></template>',
+  ],
+
+  invalid: [
+    // === Upstream parity — missing title ===
+    {
+      code: '<template><iframe /></template>',
+      output: null,
+      errors: [{ messageId: 'missingTitle' }],
+    },
+    {
+      code: '<template><iframe src="/content"></iframe></template>',
+      output: null,
+      errors: [{ messageId: 'missingTitle' }],
+    },
+
+    // === Upstream parity — empty title string ===
+    // jsx-a11y, vue-a11y, lit-a11y all flag `title=""`.
+    {
+      code: '<template><iframe title="" /></template>',
+      output: null,
+      errors: [{ messageId: 'emptyTitle' }],
+    },
+    // Whitespace-only title — ours trims then flags empty.
+    // jsx-a11y: `getLiteralPropValue("   ")` yields "   " which is truthy, so
+    // jsx-a11y would NOT flag. vue-a11y similarly does not trim. Ours trims.
+    // DIVERGENCE — we over-flag whitespace-only titles.
+    {
+      code: '<template><iframe title="   " /></template>',
+      output: null,
+      errors: [{ messageId: 'emptyTitle' }],
+    },
+
+    // === Parity — title is literal boolean / null / undefined / number ===
+    // jsx-a11y: INVALID for any non-string literal (via getLiteralPropValue
+    //   truthiness + string-check). vue-a11y: same. Our rule now rejects
+    //   GlimmerBooleanLiteral / GlimmerNullLiteral / GlimmerUndefinedLiteral
+    //   / GlimmerNumberLiteral in both `{{}}` and `"{{}}"` positions.
+    {
+      code: '<template><iframe title={{false}} /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral' }],
+    },
+    {
+      code: '<template><iframe title={{true}} /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral' }],
+    },
+    {
+      code: '<template><iframe title={{null}} /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral' }],
+    },
+    {
+      code: '<template><iframe title={{undefined}} /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral' }],
+    },
+    {
+      code: '<template><iframe title={{42}} /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral' }],
+    },
+    // Concat form — `title="{{false}}"` / etc. also flagged.
+    {
+      code: '<template><iframe title="{{false}}" /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral' }],
+    },
+    {
+      code: '<template><iframe title="{{null}}" /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral' }],
+    },
+    {
+      code: '<template><iframe title="{{42}}" /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral' }],
+    },
+
+    // === DIVERGENCE — duplicate-title detection ===
+    // jsx-a11y, vue-a11y, lit-a11y: do NOT check for duplicate titles across
+    // multiple iframes. Our rule does (inherited from ember-template-lint).
+    // Captured here as one of our OVER-flagging cases (intentional extension).
+    {
+      code: '<template><iframe title="foo" /><iframe title="foo" /></template>',
+      output: null,
+      errors: [
+        { message: 'This title is not unique. #1' },
+        {
+          message:
+            '<iframe> elements must have a unique title property. Value title="foo" already used for different iframe. #1',
+        },
+      ],
+    },
+  ],
+});
+
+const hbsRuleTester = new RuleTester({
+  parser: require.resolve('ember-eslint-parser/hbs'),
+  parserOptions: { ecmaVersion: 2022, sourceType: 'module' },
+});
+
+hbsRuleTester.run('audit:iframe-title (hbs)', rule, {
+  valid: [
+    '<iframe title="Welcome" />',
+    '<iframe title={{someValue}} />',
+    // DIVERGENCE — exempted (see gts section)
+    '<iframe aria-hidden="true" />',
+    '<iframe hidden />',
+  ],
+  invalid: [
+    {
+      code: '<iframe />',
+      output: null,
+      errors: [{ messageId: 'missingTitle' }],
+    },
+    {
+      code: '<iframe title="" />',
+      output: null,
+      errors: [{ messageId: 'emptyTitle' }],
+    },
+    // Parity — non-string literal titles.
+    {
+      code: '<iframe title={{false}} />',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral' }],
+    },
+    {
+      code: '<iframe title={{undefined}} />',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral' }],
+    },
+    {
+      code: '<iframe title={{42}} />',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral' }],
+    },
+    // DIVERGENCE — duplicate detection (upstream does not check).
+    {
+      code: '<iframe title="foo" /><iframe title="foo" />',
+      output: null,
+      errors: [
+        { message: 'This title is not unique. #1' },
+        {
+          message:
+            '<iframe> elements must have a unique title property. Value title="foo" already used for different iframe. #1',
+        },
+      ],
+    },
+  ],
+});
diff --git a/tests/lib/rules/template-require-iframe-title.js b/tests/lib/rules/template-require-iframe-title.js
index 25d4f9545a..e5be362d89 100644
--- a/tests/lib/rules/template-require-iframe-title.js
+++ b/tests/lib/rules/template-require-iframe-title.js
@@ -18,6 +18,11 @@ ruleTester.run('template-require-iframe-title', rule, {
     '<template><iframe title="" aria-hidden /></template>',
     '<template><iframe title="" hidden /></template>',
     '<template><iframe title="foo" /><iframe title="bar" /></template>',
+    // allowWhitespaceOnlyTitle: true — whitespace-only accepted.
+    {
+      code: '<template><iframe title="   " /></template>',
+      options: [{ allowWhitespaceOnlyTitle: true }],
+    },
   ],
   invalid: [
     {
@@ -92,18 +97,65 @@ ruleTester.run('template-require-iframe-title', rule, {
     {
       code: '<template><iframe src="12" title={{false}} /></template>',
       output: null,
-      errors: [{ messageId: 'dynamicFalseTitle' }],
+      errors: [{ messageId: 'invalidTitleLiteral', data: { literalType: 'boolean' } }],
     },
     {
       code: '<template><iframe src="12" title="{{false}}" /></template>',
       output: null,
-      errors: [{ messageId: 'dynamicFalseTitle' }],
+      errors: [{ messageId: 'invalidTitleLiteral', data: { literalType: 'boolean' } }],
     },
     {
       code: '<template><iframe src="12" title="" /></template>',
       output: null,
       errors: [{ messageId: 'emptyTitle' }],
     },
+
+    // Mustache literals that don't coerce to a useful accessible name.
+    {
+      code: '<template><iframe title={{null}} /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral', data: { literalType: 'null' } }],
+    },
+    {
+      code: '<template><iframe title={{undefined}} /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral', data: { literalType: 'undefined' } }],
+    },
+    {
+      code: '<template><iframe title={{42}} /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral', data: { literalType: 'number' } }],
+    },
+    {
+      code: '<template><iframe title="{{null}}" /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral', data: { literalType: 'null' } }],
+    },
+    {
+      code: '<template><iframe title="{{undefined}}" /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral', data: { literalType: 'undefined' } }],
+    },
+    {
+      code: '<template><iframe title="{{42}}" /></template>',
+      output: null,
+      errors: [{ messageId: 'invalidTitleLiteral', data: { literalType: 'number' } }],
+    },
+
+    // Whitespace-only title is flagged by default (authoring hygiene).
+    {
+      code: '<template><iframe title="   " /></template>',
+      output: null,
+      errors: [{ messageId: 'emptyTitle' }],
+    },
+    // Empty-string title is flagged even with allowWhitespaceOnlyTitle: true
+    // (an empty string is not a whitespace string).
+    {
+      code: '<template><iframe title="" /></template>',
+      output: null,
+      options: [{ allowWhitespaceOnlyTitle: true }],
+      errors: [{ messageId: 'emptyTitle' }],
+    },
   ],
 });
 
@@ -177,17 +229,70 @@ hbsRuleTester.run('template-require-iframe-title', rule, {
     {
       code: '<iframe src="12" title={{false}} />',
       output: null,
-      errors: [{ message: '<iframe> elements must have a unique title property.' }],
+      errors: [
+        {
+          message:
+            '<iframe title> must be a non-empty string. Got a boolean literal, which does not describe the frame contents.',
+        },
+      ],
     },
     {
       code: '<iframe src="12" title="{{false}}" />',
       output: null,
-      errors: [{ message: '<iframe> elements must have a unique title property.' }],
+      errors: [
+        {
+          message:
+            '<iframe title> must be a non-empty string. Got a boolean literal, which does not describe the frame contents.',
+        },
+      ],
     },
     {
       code: '<iframe src="12" title="" />',
       output: null,
       errors: [{ message: '<iframe> elements must have a unique title property.' }],
     },
+
+    // hbs parity with gjs for the other non-string mustache literals
+    // (boolean true / null / undefined / number).
+    {
+      code: '<iframe title={{true}} />',
+      output: null,
+      errors: [
+        {
+          message:
+            '<iframe title> must be a non-empty string. Got a boolean literal, which does not describe the frame contents.',
+        },
+      ],
+    },
+    {
+      code: '<iframe title={{null}} />',
+      output: null,
+      errors: [
+        {
+          message:
+            '<iframe title> must be a non-empty string. Got a null literal, which does not describe the frame contents.',
+        },
+      ],
+    },
+    {
+      code: '<iframe title={{undefined}} />',
+      output: null,
+      errors: [
+        {
+          message:
+            '<iframe title> must be a non-empty string. Got a undefined literal, which does not describe the frame contents.',
+        },
+      ],
+    },
+    {
+      code: '<iframe title={{42}} />',
+      output: null,
+      errors: [
+        {
+          message:
+            '<iframe title> must be a non-empty string. Got a number literal, which does not describe the frame contents.',
+        },
+      ],
+    },
   ],
 });