diff --git a/.changeset/rich-text-input-min-max-lines.md b/.changeset/rich-text-input-min-max-lines.md
new file mode 100644
index 000000000..c2a063cf1
--- /dev/null
+++ b/.changeset/rich-text-input-min-max-lines.md
@@ -0,0 +1,5 @@
+---
+"@slack/types": minor
+---
+
+feat(types): add optional `min_lines` and `max_lines` properties to `RichTextInput` element
diff --git a/packages/types/src/block-kit/block-elements.ts b/packages/types/src/block-kit/block-elements.ts
index 2fd445a34..005f7ed60 100644
--- a/packages/types/src/block-kit/block-elements.ts
+++ b/packages/types/src/block-kit/block-elements.ts
@@ -1066,4 +1066,13 @@ export interface RichTextInput extends Actionable, Dispatchable, Focusable, Plac
    * @description Initial contents of the input when it is loaded.
    */
   initial_value?: RichTextBlock;
+  /**
+   * @description The minimum number of lines of text shown in the input. Must be between 1 and 50.
+   */
+  min_lines?: number;
+  /**
+   * @description The maximum number of lines of text shown in the input before it scrolls. Must be between 1 and 50.
+   * Defaults to `8` when not specified.
+   */
+  max_lines?: number;
 }
diff --git a/packages/types/test/block-elements.test-d.ts b/packages/types/test/block-elements.test-d.ts
new file mode 100644
index 000000000..0c07deb1d
--- /dev/null
+++ b/packages/types/test/block-elements.test-d.ts
@@ -0,0 +1,30 @@
+import { expectAssignable, expectError } from 'tsd';
+import type { RichTextInput } from '../src/index';
+
+// RichTextInput — happy paths
+expectAssignable<RichTextInput>({
+  type: 'rich_text_input',
+});
+expectAssignable<RichTextInput>({
+  type: 'rich_text_input',
+  min_lines: 3,
+});
+expectAssignable<RichTextInput>({
+  type: 'rich_text_input',
+  max_lines: 16,
+});
+expectAssignable<RichTextInput>({
+  type: 'rich_text_input',
+  min_lines: 3,
+  max_lines: 16,
+});
+
+// RichTextInput — sad paths
+expectError<RichTextInput>({
+  type: 'rich_text_input',
+  min_lines: '3',
+});
+expectError<RichTextInput>({
+  type: 'rich_text_input',
+  max_lines: '16',
+});