diff --git a/src/wp-admin/includes/meta-boxes.php b/src/wp-admin/includes/meta-boxes.php
index c52b4787a3044..344d673ccc129 100644
--- a/src/wp-admin/includes/meta-boxes.php
+++ b/src/wp-admin/includes/meta-boxes.php
@@ -181,7 +181,7 @@ function post_submit_meta_box( $post, $args = array() ) {
 				} elseif ( ! empty( $post->post_password ) ) {
 					$visibility       = 'password';
 					$visibility_trans = __( 'Password protected' );
-				} elseif ( 'post' === $post_type && is_sticky( $post_id ) ) {
+				} elseif ( post_type_supports( $post_type, 'sticky' ) && is_sticky( $post_id ) ) {
 					$visibility       = 'public';
 					$visibility_trans = __( 'Public, Sticky' );
 				} else {
@@ -210,7 +210,7 @@ function post_submit_meta_box( $post, $args = array() ) {
 					<input type="hidden" name="hidden_post_visibility" id="hidden-post-visibility" value="<?php echo esc_attr( $visibility ); ?>" />
 					<input type="radio" name="visibility" id="visibility-radio-public" value="public" <?php checked( $visibility, 'public' ); ?> /> <label for="visibility-radio-public" class="selectit"><?php _e( 'Public' ); ?></label><br />
 
-					<?php if ( 'post' === $post_type && current_user_can( 'edit_others_posts' ) ) : ?>
+					<?php if ( post_type_supports( $post_type, 'sticky' ) && current_user_can( 'edit_others_posts' ) ) : ?>
 						<span id="sticky-span"><input id="sticky" name="sticky" type="checkbox" value="sticky" <?php checked( is_sticky( $post_id ) ); ?> /> <label for="sticky" class="selectit"><?php _e( 'Stick this post to the front page' ); ?></label><br /></span>
 					<?php endif; ?>
 
diff --git a/src/wp-admin/includes/template.php b/src/wp-admin/includes/template.php
index 25fb44ad71890..020a13ce41941 100644
--- a/src/wp-admin/includes/template.php
+++ b/src/wp-admin/includes/template.php
@@ -376,7 +376,7 @@ function get_inline_data( $post ) {
 		}
 	}
 
-	if ( ! $post_type_object->hierarchical ) {
+	if ( post_type_supports( $post->post_type, 'sticky' ) ) {
 		echo '<div class="sticky">' . ( is_sticky( $post->ID ) ? 'sticky' : '' ) . '</div>';
 	}
 
diff --git a/src/wp-includes/class-wp-xmlrpc-server.php b/src/wp-includes/class-wp-xmlrpc-server.php
index 7c1e101e1e091..c8eb9dcb31aa5 100644
--- a/src/wp-includes/class-wp-xmlrpc-server.php
+++ b/src/wp-includes/class-wp-xmlrpc-server.php
@@ -939,7 +939,7 @@ protected function _prepare_post( $post, $fields ) {
 			'menu_order'        => (int) $post['menu_order'],
 			'comment_status'    => $post['comment_status'],
 			'ping_status'       => $post['ping_status'],
-			'sticky'            => ( 'post' === $post['post_type'] && is_sticky( $post['ID'] ) ),
+			'sticky'            => ( post_type_supports( $post['post_type'], 'sticky' ) && is_sticky( $post['ID'] ) ),
 		);
 
 		// Thumbnail.
@@ -1466,10 +1466,8 @@ protected function _insert_post( $user, $content_struct ) {
 			if ( get_post_type( $post_data['ID'] ) !== $post_data['post_type'] ) {
 				return new IXR_Error( 401, __( 'The post type may not be changed.' ) );
 			}
-		} else {
-			if ( ! current_user_can( $post_type->cap->create_posts ) || ! current_user_can( $post_type->cap->edit_posts ) ) {
+		} elseif ( ! current_user_can( $post_type->cap->create_posts ) || ! current_user_can( $post_type->cap->edit_posts ) ) {
 				return new IXR_Error( 401, __( 'Sorry, you are not allowed to post on this site.' ) );
-			}
 		}
 
 		switch ( $post_data['post_status'] ) {
@@ -6071,10 +6069,8 @@ public function mw_editPost( $args ) {
 			// Empty value deletes, non-empty value adds/updates.
 			if ( empty( $content_struct['wp_post_thumbnail'] ) ) {
 				delete_post_thumbnail( $post_id );
-			} else {
-				if ( set_post_thumbnail( $post_id, $content_struct['wp_post_thumbnail'] ) === false ) {
+			} elseif ( set_post_thumbnail( $post_id, $content_struct['wp_post_thumbnail'] ) === false ) {
 					return new IXR_Error( 404, __( 'Invalid attachment ID.' ) );
-				}
 			}
 			unset( $content_struct['wp_post_thumbnail'] );
 		}
@@ -6363,7 +6359,7 @@ public function mw_getRecentPosts( $args ) {
 				'wp_post_format'         => $post_format,
 				'date_modified'          => $post_modified,
 				'date_modified_gmt'      => $post_modified_gmt,
-				'sticky'                 => ( 'post' === $entry['post_type'] && is_sticky( $entry['ID'] ) ),
+				'sticky'                 => ( post_type_supports( $entry['post_type'], 'sticky' ) && is_sticky( $entry['ID'] ) ),
 				'wp_post_thumbnail'      => get_post_thumbnail_id( $entry['ID'] ),
 			);
 		}
diff --git a/src/wp-includes/post.php b/src/wp-includes/post.php
index a2d8fba9db341..68fb4ea473f34 100644
--- a/src/wp-includes/post.php
+++ b/src/wp-includes/post.php
@@ -43,6 +43,7 @@ function create_initial_post_types() {
 			'rest_controller_class' => 'WP_REST_Posts_Controller',
 		)
 	);
+	add_post_type_support( 'post', 'sticky' );
 
 	register_post_type(
 		'page',
@@ -643,7 +644,8 @@ function create_initial_post_types() {
 		array(
 			'label'       => _x( 'Published', 'post status' ),
 			'public'      => true,
-			'_builtin'    => true, /* internal use only. */
+			'_builtin'    => true, /*
+		internal use only. */
 			/* translators: %s: Number of published posts. */
 			'label_count' => _n_noop(
 				'Published <span class="count">(%s)</span>',
@@ -657,7 +659,8 @@ function create_initial_post_types() {
 		array(
 			'label'       => _x( 'Scheduled', 'post status' ),
 			'protected'   => true,
-			'_builtin'    => true, /* internal use only. */
+			'_builtin'    => true, /*
+		internal use only. */
 			/* translators: %s: Number of scheduled posts. */
 			'label_count' => _n_noop(
 				'Scheduled <span class="count">(%s)</span>',
@@ -671,7 +674,8 @@ function create_initial_post_types() {
 		array(
 			'label'         => _x( 'Draft', 'post status' ),
 			'protected'     => true,
-			'_builtin'      => true, /* internal use only. */
+			'_builtin'      => true, /*
+		internal use only. */
 			/* translators: %s: Number of draft posts. */
 			'label_count'   => _n_noop(
 				'Draft <span class="count">(%s)</span>',
@@ -686,7 +690,8 @@ function create_initial_post_types() {
 		array(
 			'label'         => _x( 'Pending', 'post status' ),
 			'protected'     => true,
-			'_builtin'      => true, /* internal use only. */
+			'_builtin'      => true, /*
+		internal use only. */
 			/* translators: %s: Number of pending posts. */
 			'label_count'   => _n_noop(
 				'Pending <span class="count">(%s)</span>',
@@ -701,7 +706,8 @@ function create_initial_post_types() {
 		array(
 			'label'       => _x( 'Private', 'post status' ),
 			'private'     => true,
-			'_builtin'    => true, /* internal use only. */
+			'_builtin'    => true, /*
+		internal use only. */
 			/* translators: %s: Number of private posts. */
 			'label_count' => _n_noop(
 				'Private <span class="count">(%s)</span>',
@@ -715,7 +721,8 @@ function create_initial_post_types() {
 		array(
 			'label'                     => _x( 'Trash', 'post status' ),
 			'internal'                  => true,
-			'_builtin'                  => true, /* internal use only. */
+			'_builtin'                  => true, /*
+		internal use only. */
 			/* translators: %s: Number of trashed posts. */
 			'label_count'               => _n_noop(
 				'Trash <span class="count">(%s)</span>',
@@ -750,7 +757,8 @@ function create_initial_post_types() {
 		array(
 			'label'               => _x( 'Pending', 'request status' ),
 			'internal'            => true,
-			'_builtin'            => true, /* internal use only. */
+			'_builtin'            => true, /*
+		internal use only. */
 			/* translators: %s: Number of pending requests. */
 			'label_count'         => _n_noop(
 				'Pending <span class="count">(%s)</span>',
@@ -765,7 +773,8 @@ function create_initial_post_types() {
 		array(
 			'label'               => _x( 'Confirmed', 'request status' ),
 			'internal'            => true,
-			'_builtin'            => true, /* internal use only. */
+			'_builtin'            => true, /*
+		internal use only. */
 			/* translators: %s: Number of confirmed requests. */
 			'label_count'         => _n_noop(
 				'Confirmed <span class="count">(%s)</span>',
@@ -780,7 +789,8 @@ function create_initial_post_types() {
 		array(
 			'label'               => _x( 'Failed', 'request status' ),
 			'internal'            => true,
-			'_builtin'            => true, /* internal use only. */
+			'_builtin'            => true, /*
+		internal use only. */
 			/* translators: %s: Number of failed requests. */
 			'label_count'         => _n_noop(
 				'Failed <span class="count">(%s)</span>',
@@ -795,7 +805,8 @@ function create_initial_post_types() {
 		array(
 			'label'               => _x( 'Completed', 'request status' ),
 			'internal'            => true,
-			'_builtin'            => true, /* internal use only. */
+			'_builtin'            => true, /*
+		internal use only. */
 			/* translators: %s: Number of completed requests. */
 			'label_count'         => _n_noop(
 				'Completed <span class="count">(%s)</span>',
@@ -2858,6 +2869,16 @@ function is_sticky( $post_id = 0 ) {
 		$post_id = get_the_ID();
 	}
 
+	$post = get_post( $post_id );
+	if ( ! $post ) {
+		return false;
+	}
+
+	// Check if the post type supports stickiness.
+	if ( ! post_type_supports( $post->post_type, 'sticky' ) ) {
+		return false;
+	}
+
 	$stickies = get_option( 'sticky_posts' );
 
 	if ( is_array( $stickies ) ) {
@@ -3263,7 +3284,15 @@ function sanitize_post_field( $field, $value, $post_id, $context = 'display' ) {
  * @param int $post_id Post ID.
  */
 function stick_post( $post_id ) {
-	$post_id  = (int) $post_id;
+	$post_id = (int) $post_id;
+
+	$post = get_post( $post_id );
+
+	// Check if the post type supports stickiness (only for existing posts).
+	if ( $post && ! post_type_supports( $post->post_type, 'sticky' ) ) {
+		return;
+	}
+
 	$stickies = get_option( 'sticky_posts' );
 	$updated  = false;
 
@@ -3300,7 +3329,13 @@ function stick_post( $post_id ) {
  * @param int $post_id Post ID.
  */
 function unstick_post( $post_id ) {
-	$post_id  = (int) $post_id;
+	$post_id = (int) $post_id;
+	$post    = get_post( $post_id );
+
+	// Check if the post type supports stickiness (only for existing posts).
+	if ( $post && ! post_type_supports( $post->post_type, 'sticky' ) ) {
+		return;
+	}
 	$stickies = get_option( 'sticky_posts' );
 
 	if ( ! is_array( $stickies ) ) {
diff --git a/tests/phpunit/tests/post/sticky.php b/tests/phpunit/tests/post/sticky.php
new file mode 100644
index 0000000000000..eef3fc0dcb181
--- /dev/null
+++ b/tests/phpunit/tests/post/sticky.php
@@ -0,0 +1,165 @@
+<?php
+/**
+ * Unit tests for stickiness and Post Type Support API integration.
+ *
+ * @package WordPress
+ * @group sticky
+ * @ticket 48954
+ */
+
+class Tests_Post_Stickiness extends WP_UnitTestCase {
+
+	/**
+	 * Set up test environment before each test.
+	 */
+	public function setUp(): void {
+		parent::setUp();
+		update_option( 'sticky_posts', array() );
+	}
+
+	/**
+	 * Clean up after each test.
+	 */
+	public function tearDown(): void {
+		$custom_types = array( 'custom_type', 'my_custom_type', 'another_type' );
+		foreach ( $custom_types as $type ) {
+			if ( post_type_exists( $type ) ) {
+				_unregister_post_type( $type );
+			}
+		}
+		update_option( 'sticky_posts', array() );
+		parent::tearDown();
+	}
+
+	/**
+	 * Test that stickiness works for post types that support it.
+	 */
+	public function test_stickiness_for_supported_post_type() {
+		$post_id = self::factory()->post->create( array( 'post_type' => 'post' ) );
+
+		stick_post( $post_id );
+		$this->assertTrue( is_sticky( $post_id ) );
+
+		unstick_post( $post_id );
+		$this->assertFalse( is_sticky( $post_id ) );
+	}
+
+	/**
+	 * Test that stickiness does not work for post types that do not support it.
+	 */
+	public function test_stickiness_for_unsupported_post_type() {
+		register_post_type(
+			'custom_type',
+			array(
+				'label'    => 'Custom Type',
+				'public'   => true,
+				'supports' => array( 'title', 'editor' ),
+			)
+		);
+
+		$post_id = self::factory()->post->create( array( 'post_type' => 'custom_type' ) );
+		stick_post( $post_id );
+		$this->assertFalse( is_sticky( $post_id ) );
+	}
+
+	/**
+	 * Test that stickiness is removed when switching to a post type that does not support it.
+	 */
+	public function test_stickiness_removed_on_post_type_switch() {
+		$post_id = self::factory()->post->create( array( 'post_type' => 'post' ) );
+		stick_post( $post_id );
+		$this->assertTrue( is_sticky( $post_id ) );
+
+		wp_update_post(
+			array(
+				'ID'        => $post_id,
+				'post_type' => 'page',
+			)
+		);
+		$this->assertFalse( is_sticky( $post_id ) );
+	}
+
+	/**
+	 * Test that UI functions handle post type switches correctly.
+	 */
+	public function test_ui_functions_after_post_type_switch() {
+		$admin_id = self::factory()->user->create( array( 'role' => 'administrator' ) );
+		wp_set_current_user( $admin_id );
+
+		$post_id = self::factory()->post->create(
+			array(
+				'post_type'   => 'post',
+				'post_author' => $admin_id,
+			)
+		);
+		stick_post( $post_id );
+
+		$states = get_post_states( get_post( $post_id ) );
+		$this->assertArrayHasKey( 'sticky', $states );
+
+		wp_update_post(
+			array(
+				'ID'        => $post_id,
+				'post_type' => 'page',
+			)
+		);
+
+		$states = get_post_states( get_post( $post_id ) );
+		$this->assertArrayNotHasKey( 'sticky', $states );
+	}
+
+	/**
+	 * Test backward compatibility - existing sticky posts behavior.
+	 */
+	public function test_backward_compatibility() {
+		$this->assertTrue( post_type_supports( 'post', 'sticky' ) );
+		$this->assertFalse( post_type_supports( 'page', 'sticky' ) );
+
+		$post_id = self::factory()->post->create( array( 'post_type' => 'post' ) );
+		stick_post( $post_id );
+		$this->assertTrue( is_sticky( $post_id ) );
+	}
+
+	/**
+	 * Test that developers can add sticky support to custom post types.
+	 */
+	public function test_custom_post_type_sticky_support() {
+		register_post_type(
+			'my_custom_type',
+			array(
+				'label'    => 'My Custom Type',
+				'public'   => true,
+				'supports' => array( 'title', 'editor', 'sticky' ),
+			)
+		);
+
+		$this->assertTrue( post_type_supports( 'my_custom_type', 'sticky' ) );
+
+		$custom_post_id = self::factory()->post->create( array( 'post_type' => 'my_custom_type' ) );
+		stick_post( $custom_post_id );
+		$this->assertTrue( is_sticky( $custom_post_id ) );
+
+		register_post_type(
+			'another_type',
+			array(
+				'label'    => 'Another Type',
+				'public'   => true,
+				'supports' => array( 'title' ),
+			)
+		);
+
+		$this->assertFalse( post_type_supports( 'another_type', 'sticky' ) );
+
+		add_post_type_support( 'another_type', 'sticky' );
+		$this->assertTrue( post_type_supports( 'another_type', 'sticky' ) );
+	}
+
+	/**
+	 * Test that post_type_supports() checks work correctly for stickiness.
+	 */
+	public function test_post_type_supports_sticky() {
+		$this->assertTrue( post_type_supports( 'post', 'sticky' ) );
+		$this->assertFalse( post_type_supports( 'page', 'sticky' ) );
+		$this->assertFalse( post_type_supports( 'attachment', 'sticky' ) );
+	}
+}