diff --git a/wp-includes/media.php b/wp-includes/media.php
index dd46e4c141..01543b9dcd 100644
--- a/wp-includes/media.php
+++ b/wp-includes/media.php
@@ -4725,7 +4725,7 @@ function get_post_galleries( $post, $html = true ) {
 		return array();
 	}
 
-	if ( ! has_shortcode( $post->post_content, 'gallery' ) ) {
+	if ( ! has_shortcode( $post->post_content, 'gallery' ) && ! has_block( 'gallery', $post->post_content ) ) {
 		return array();
 	}
 
@@ -4767,6 +4767,95 @@ function get_post_galleries( $post, $html = true ) {
 		}
 	}
 
+	if ( has_block( 'gallery', $post->post_content ) ) {
+		$post_blocks = parse_blocks( $post->post_content );
+
+		while ( $block = array_shift( $post_blocks ) ) {
+			$has_inner_blocks = ! empty( $block['innerBlocks'] );
+
+			// Skip blocks with no blockName and no innerHTML.
+			if ( ! $block['blockName'] ) {
+				continue;
+			}
+
+			// All blocks nested inside non-Gallery blocks should be in the root array.
+			if ( $has_inner_blocks && 'core/gallery' !== $block['blockName'] ) {
+				array_push( $post_blocks, ...$block['innerBlocks'] );
+				continue;
+			}
+
+			// New Gallery block format as HTML.
+			if ( $has_inner_blocks && $html ) {
+				$block_html  = wp_list_pluck( $block['innerBlocks'], 'innerHTML' );
+				$galleries[] = '<figure>' . implode( ' ', $block_html ) . '</figure>';
+				continue;
+			}
+
+			$srcs = array();
+
+			// New Gallery block format as an array.
+			if ( $has_inner_blocks ) {
+				$attrs = wp_list_pluck( $block['innerBlocks'], 'attrs' );
+				$ids   = wp_list_pluck( $attrs, 'id' );
+
+				foreach ( $ids as $id ) {
+					$url = wp_get_attachment_url( $id );
+
+					if ( is_string( $url ) && ! in_array( $url, $srcs, true ) ) {
+						$srcs[] = $url;
+					}
+				}
+
+				$galleries[] = array(
+					'ids' => implode( ',', $ids ),
+					'src' => $srcs,
+				);
+
+				continue;
+			}
+
+			// Old Gallery block format as HTML.
+			if ( $html ) {
+				$galleries[] = $block['innerHTML'];
+				continue;
+			}
+
+			// Old Gallery block format as an array.
+			$ids = ! empty( $block['attrs']['ids'] ) ? $block['attrs']['ids'] : array();
+
+			// If present, use the image IDs from the JSON blob as canonical.
+			if ( ! empty( $ids ) ) {
+				foreach ( $ids as $id ) {
+					$url = wp_get_attachment_url( $id );
+
+					if ( is_string( $url ) && ! in_array( $url, $srcs, true ) ) {
+						$srcs[] = $url;
+					}
+				}
+
+				$galleries[] = array(
+					'ids' => implode( ',', $ids ),
+					'src' => $srcs,
+				);
+
+				continue;
+			}
+
+			// Otherwise, extract srcs from the innerHTML.
+			preg_match_all( '#src=([\'"])(.+?)\1#is', $block['innerHTML'], $found_srcs, PREG_SET_ORDER );
+
+			if ( ! empty( $found_srcs[0] ) ) {
+				foreach ( $found_srcs as $src ) {
+					if ( isset( $src[2] ) && ! in_array( $src[2], $srcs, true ) ) {
+						$srcs[] = $src[2];
+					}
+				}
+			}
+
+			$galleries[] = array( 'src' => $srcs );
+		}
+	}
+
 	/**
 	 * Filters the list of all found galleries in the given post.
 	 *
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 82369b3ee6..a688a97fdc 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-52189';
+$wp_version = '5.9-alpha-52190';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.