diff --git a/docs/architecture.md b/docs/architecture.md
index f7f30f2..4846919 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -53,6 +53,7 @@ Accessibility-oriented helpers are also provided for common attribute patterns:
 - `AriaHidden(node, hidden)`
 - `AriaExpanded(node, expanded)`
 - `AriaDisabled(node, disabled)`
+- `AriaModal(node, modal)`
 - `AriaChecked(node, checked)`
 - `AriaInvalid(node, invalid)`
 - `AriaRequired(node, required)`
diff --git a/docs/index.md b/docs/index.md
index 1a11d63..f6eea63 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -39,7 +39,7 @@ This builds a Header-Content-Footer layout with semantic HTML elements (`<header
 
 | Path | Purpose |
 |------|---------|
-| `node.go` | `Node` interface and all node types: `El`, `Text`, `Raw`, `If`, `Unless`, `Each`, `EachSeq`, `Switch`, `Entitled`, plus `AriaLabel`, `AriaControls`, `AriaHasPopup`, `AriaOwns`, `AriaKeyShortcuts`, `Alt`/`AltText`, `AriaBusy`, `AriaLive`, `AriaDisabled`, `AriaChecked`, `AriaInvalid`, `AriaRequired`, `AriaPressed`, `AriaSelected`, `Hidden`, `TabIndex`, and `AutoFocus` helpers |
+| `node.go` | `Node` interface and all node types: `El`, `Text`, `Raw`, `If`, `Unless`, `Each`, `EachSeq`, `Switch`, `Entitled`, plus `AriaLabel`, `AriaControls`, `AriaHasPopup`, `AriaOwns`, `AriaKeyShortcuts`, `Alt`/`AltText`, `AriaBusy`, `AriaLive`, `AriaDisabled`, `AriaModal`, `AriaChecked`, `AriaInvalid`, `AriaRequired`, `AriaPressed`, `AriaSelected`, `Hidden`, `TabIndex`, and `AutoFocus` helpers |
 | `layout.go` | HLCRF compositor with semantic HTML elements and ARIA roles |
 | `responsive.go` | Multi-variant breakpoint wrapper (`data-variant` containers, CSS scoping helpers) |
 | `context.go` | Rendering context: identity, locale, entitlements, i18n service |
@@ -52,7 +52,7 @@ This builds a Header-Content-Footer layout with semantic HTML elements (`<header
 
 ## Key Concepts
 
-**Node tree** -- All renderable units implement `Node`, a single-method interface: `Render(ctx *Context) string`. The library composes nodes into trees using `El()` for elements, `Text()` for translated text, and control-flow constructors (`If`, `Unless`, `Each`, `Switch`, `Entitled`), plus accessibility and visibility helpers such as `AriaLabel()`, `AriaControls()`, `AriaHasPopup()`, `AriaOwns()`, `AriaKeyShortcuts()`, `AriaCurrent()`, `AriaBusy()`, `AriaLive()`, `AriaHidden()`, `Hidden()`, `AriaDisabled()`, `AriaChecked()`, `AriaInvalid()`, `AriaRequired()`, `AriaReadOnly()`, and `TabIndex()`.
+**Node tree** -- All renderable units implement `Node`, a single-method interface: `Render(ctx *Context) string`. The library composes nodes into trees using `El()` for elements, `Text()` for translated text, and control-flow constructors (`If`, `Unless`, `Each`, `Switch`, `Entitled`), plus accessibility and visibility helpers such as `AriaLabel()`, `AriaControls()`, `AriaHasPopup()`, `AriaOwns()`, `AriaKeyShortcuts()`, `AriaCurrent()`, `AriaBusy()`, `AriaLive()`, `AriaHidden()`, `Hidden()`, `AriaDisabled()`, `AriaModal()`, `AriaChecked()`, `AriaInvalid()`, `AriaRequired()`, `AriaReadOnly()`, and `TabIndex()`.
 
 **HLCRF Layout** -- A five-slot compositor that maps to semantic HTML: `<header>` (H), `<aside>` (L/R), `<main>` (C), `<footer>` (F). The variant string controls which slots render: `"HLCRF"` for all five, `"HCF"` for three, `"C"` for content only. Layouts nest: placing a `Layout` inside another layout's slot produces hierarchical `data-block` paths like `L-0-C-0`.
 
diff --git a/node.go b/node.go
index ba7d4de..4859bb4 100644
--- a/node.go
+++ b/node.go
@@ -389,6 +389,15 @@ func AriaDisabled(n Node, disabled bool) Node {
 	return Attr(n, "aria-disabled", "false")
 }
 
+// node.go: AriaModal sets the aria-modal attribute on an element node.
+// Example: AriaModal(El("dialog"), true).
+func AriaModal(n Node, modal bool) Node {
+	if modal {
+		return Attr(n, "aria-modal", "true")
+	}
+	return Attr(n, "aria-modal", "false")
+}
+
 // node.go: AriaChecked sets the aria-checked attribute on an element node.
 // Example: AriaChecked(El("input"), true).
 func AriaChecked(n Node, checked bool) Node {
diff --git a/node_test.go b/node_test.go
index 79f4246..2db904f 100644
--- a/node_test.go
+++ b/node_test.go
@@ -706,6 +706,22 @@ func TestAriaDisabledHelper(t *testing.T) {
 	}
 }
 
+func TestAriaModalHelper(t *testing.T) {
+	ctx := NewContext()
+
+	modal := AriaModal(El("dialog", Raw("content")), true)
+	gotModal := modal.Render(ctx)
+	if !strings.Contains(gotModal, `aria-modal="true"`) {
+		t.Errorf("AriaModal(true) = %q, want aria-modal=\"true\"", gotModal)
+	}
+
+	nonModal := AriaModal(El("dialog", Raw("content")), false)
+	gotNonModal := nonModal.Render(ctx)
+	if !strings.Contains(gotNonModal, `aria-modal="false"`) {
+		t.Errorf("AriaModal(false) = %q, want aria-modal=\"false\"", gotNonModal)
+	}
+}
+
 func TestAriaCheckedHelper(t *testing.T) {
 	ctx := NewContext()