diff --git a/lib/block-supports/layout.php b/lib/block-supports/layout.php
index 56d893ae7d3dfb..92763e010d7756 100644
--- a/lib/block-supports/layout.php
+++ b/lib/block-supports/layout.php
@@ -28,12 +28,13 @@ function gutenberg_register_layout_support( $block_type ) {
 /**
  * Generates the CSS corresponding to the provided layout.
  *
- * @param string $selector CSS selector.
- * @param array  $layout   Layout object.
+ * @param string  $selector CSS selector.
+ * @param array   $layout   Layout object.
+ * @param boolean $has_block_gap_support Whether the theme has support for the block gap.
  *
  * @return string CSS style.
  */
-function gutenberg_get_layout_style( $selector, $layout ) {
+function gutenberg_get_layout_style( $selector, $layout, $has_block_gap_support = false ) {
 	$layout_type = isset( $layout['type'] ) ? $layout['type'] : 'default';
 
 	$style = '';
@@ -63,11 +64,17 @@ function gutenberg_get_layout_style( $selector, $layout ) {
 
 		$style .= "$selector .alignleft { float: left; margin-right: 2em; }";
 		$style .= "$selector .alignright { float: right; margin-left: 2em; }";
-		$style .= "$selector > * + * { margin-top: var( --wp--style--block-gap ); margin-bottom: 0; }";
+		if ( $has_block_gap_support ) {
+			$style .= "$selector > * + * { margin-top: var( --wp--style--block-gap ); margin-bottom: 0; }";
+		}
 	} elseif ( 'flex' === $layout_type ) {
 		$style  = "$selector {";
 		$style .= 'display: flex;';
-		$style .= 'gap: var( --wp--style--block-gap, 0.5em );';
+		if ( $has_block_gap_support ) {
+			$style .= 'gap: var( --wp--style--block-gap, 0.5em );';
+		} else {
+			$style .= 'gap: 0.5em;';
+		}
 		$style .= 'flex-wrap: wrap;';
 		$style .= 'align-items: center;';
 		$style .= '}';
@@ -93,11 +100,13 @@ function gutenberg_render_layout_support_flag( $block_content, $block ) {
 		return $block_content;
 	}
 
-	$default_block_layout = _wp_array_get( $block_type->supports, array( '__experimentalLayout', 'default' ), array() );
-	$used_layout          = isset( $block['attrs']['layout'] ) ? $block['attrs']['layout'] : $default_block_layout;
+	$tree                  = WP_Theme_JSON_Resolver_Gutenberg::get_merged_data( array(), 'theme' );
+	$theme_settings        = $tree->get_settings();
+	$default_layout        = _wp_array_get( $theme_settings, array( 'layout' ) );
+	$has_block_gap_support = isset( $theme_settings['spacing']['blockGap'] ) ? null !== $theme_settings['spacing']['blockGap'] : false;
+	$default_block_layout  = _wp_array_get( $block_type->supports, array( '__experimentalLayout', 'default' ), array() );
+	$used_layout           = isset( $block['attrs']['layout'] ) ? $block['attrs']['layout'] : $default_block_layout;
 	if ( isset( $used_layout['inherit'] ) && $used_layout['inherit'] ) {
-		$tree           = WP_Theme_JSON_Resolver_Gutenberg::get_merged_data( array(), 'theme' );
-		$default_layout = _wp_array_get( $tree->get_settings(), array( 'layout' ) );
 		if ( ! $default_layout ) {
 			return $block_content;
 		}
@@ -105,7 +114,7 @@ function gutenberg_render_layout_support_flag( $block_content, $block ) {
 	}
 
 	$id    = uniqid();
-	$style = gutenberg_get_layout_style( ".wp-container-$id", $used_layout );
+	$style = gutenberg_get_layout_style( ".wp-container-$id", $used_layout, $has_block_gap_support );
 	// This assumes the hook only applies to blocks with a single wrapper.
 	// I think this is a reasonable limitation for that particular hook.
 	$content = preg_replace(
diff --git a/lib/class-wp-theme-json-gutenberg.php b/lib/class-wp-theme-json-gutenberg.php
index 474294caa2a218..b3f2cbe6fd2c34 100644
--- a/lib/class-wp-theme-json-gutenberg.php
+++ b/lib/class-wp-theme-json-gutenberg.php
@@ -103,6 +103,7 @@ class WP_Theme_JSON_Gutenberg {
 			'customMargin'  => null,
 			'customPadding' => null,
 			'units'         => null,
+			'blockGap'      => null,
 		),
 		'typography' => array(
 			'customFontSize'        => null,
@@ -818,7 +819,10 @@ private function get_block_classes( $style_nodes ) {
 			$block_rules .= self::to_ruleset( $selector, $declarations );
 
 			if ( self::ROOT_BLOCK_SELECTOR === $selector ) {
-				$block_rules .= '.wp-site-blocks > * + * { margin-top: var( --wp--style--block-gap ); margin-bottom: 0; }';
+				$has_block_gap_support = _wp_array_get( $this->theme_json, array( 'settings', 'spacing', 'blockGap' ) ) !== null;
+				if ( $has_block_gap_support ) {
+					$block_rules .= '.wp-site-blocks > * + * { margin-top: var( --wp--style--block-gap ); margin-bottom: 0; }';
+				}
 			}
 		}
 
diff --git a/lib/theme.json b/lib/theme.json
index 5d952b381ef932..37ccaf0c010df8 100644
--- a/lib/theme.json
+++ b/lib/theme.json
@@ -211,7 +211,7 @@
 			]
 		},
 		"spacing": {
-			"blockGap": false,
+			"blockGap": null,
 			"customMargin": false,
 			"customPadding": false,
 			"units": [ "px", "em", "rem", "vh", "vw", "%" ]
diff --git a/packages/block-editor/src/layouts/flex.js b/packages/block-editor/src/layouts/flex.js
index d130468b93ceec..268674ee3e503e 100644
--- a/packages/block-editor/src/layouts/flex.js
+++ b/packages/block-editor/src/layouts/flex.js
@@ -7,6 +7,7 @@ import { __ } from '@wordpress/i18n';
  * Internal dependencies
  */
 import { appendSelectors } from './utils';
+import useSetting from '../components/use-setting';
 
 export default {
 	name: 'flex',
@@ -18,11 +19,18 @@ export default {
 	},
 
 	save: function FlexLayoutStyle( { selector } ) {
+		const blockGapSupport = useSetting( 'spacing.blockGap' );
+		const hasBlockGapStylesSupport = blockGapSupport !== null;
+
 		return (
 			<style>{ `
 				${ appendSelectors( selector ) } {
 					display: flex;
-					gap: var( --wp--style--block-gap, 0.5em );
+					gap: ${
+						hasBlockGapStylesSupport
+							? 'var( --wp--style--block-gap, 0.5em )'
+							: '0.5em'
+					};
 					flex-wrap: wrap;
 					align-items: center;
 				}
diff --git a/packages/block-editor/src/layouts/flow.js b/packages/block-editor/src/layouts/flow.js
index 2a57f34822d165..3e0fc374ee5483 100644
--- a/packages/block-editor/src/layouts/flow.js
+++ b/packages/block-editor/src/layouts/flow.js
@@ -104,6 +104,8 @@ export default {
 
 	save: function DefaultLayoutStyle( { selector, layout = {} } ) {
 		const { contentSize, wideSize } = layout;
+		const blockGapSupport = useSetting( 'spacing.blockGap' );
+		const hasBlockGapStylesSupport = blockGapSupport !== null;
 
 		let style =
 			!! contentSize || !! wideSize
@@ -135,12 +137,17 @@ export default {
 				margin-left: 2em;
 			}
 
-			${ appendSelectors( selector, '> * + *' ) } {
-				margin-top: var( --wp--style--block-gap );
-				margin-bottom: 0;
-			}
 		`;
 
+		if ( hasBlockGapStylesSupport ) {
+			style += `
+				${ appendSelectors( selector, '> * + *' ) } {
+					margin-top: var( --wp--style--block-gap );
+					margin-bottom: 0;
+				}
+			`;
+		}
+
 		return <style>{ style }</style>;
 	},
 
diff --git a/phpunit/class-wp-theme-json-schema-v0-test.php b/phpunit/class-wp-theme-json-schema-v0-test.php
index 442e917220c58e..d3f8bce0b2b530 100644
--- a/phpunit/class-wp-theme-json-schema-v0-test.php
+++ b/phpunit/class-wp-theme-json-schema-v0-test.php
@@ -471,11 +471,11 @@ function test_get_stylesheet() {
 		);
 
 		$this->assertEquals(
-			'body{--wp--preset--color--grey: grey;--wp--preset--font-family--small: 14px;--wp--preset--font-family--big: 41px;}.wp-block-group{--wp--custom--base-font: 16;--wp--custom--line-height--small: 1.2;--wp--custom--line-height--medium: 1.4;--wp--custom--line-height--large: 1.8;}body{color: var(--wp--preset--color--grey);}.wp-site-blocks > * + * { margin-top: var( --wp--style--block-gap ); margin-bottom: 0; }a{color: #111;}h1{font-size: 1em;}h2{font-size: 2em;}.wp-block-group{padding-top: 12px;padding-bottom: 24px;}.wp-block-group a{color: #333;}h1 a,h2 a,h3 a,h4 a,h5 a,h6 a{color: #222;}.wp-block-post-title{font-size: 5em;}.wp-block-post-title a{color: #555;}.wp-block-query-title{font-size: 5em;}.wp-block-query-title a{color: #555;}.has-grey-color{color: var(--wp--preset--color--grey) !important;}.has-grey-background-color{background-color: var(--wp--preset--color--grey) !important;}.has-grey-border-color{border-color: var(--wp--preset--color--grey) !important;}',
+			'body{--wp--preset--color--grey: grey;--wp--preset--font-family--small: 14px;--wp--preset--font-family--big: 41px;}.wp-block-group{--wp--custom--base-font: 16;--wp--custom--line-height--small: 1.2;--wp--custom--line-height--medium: 1.4;--wp--custom--line-height--large: 1.8;}body{color: var(--wp--preset--color--grey);}a{color: #111;}h1{font-size: 1em;}h2{font-size: 2em;}.wp-block-group{padding-top: 12px;padding-bottom: 24px;}.wp-block-group a{color: #333;}h1 a,h2 a,h3 a,h4 a,h5 a,h6 a{color: #222;}.wp-block-post-title{font-size: 5em;}.wp-block-post-title a{color: #555;}.wp-block-query-title{font-size: 5em;}.wp-block-query-title a{color: #555;}.has-grey-color{color: var(--wp--preset--color--grey) !important;}.has-grey-background-color{background-color: var(--wp--preset--color--grey) !important;}.has-grey-border-color{border-color: var(--wp--preset--color--grey) !important;}',
 			$theme_json->get_stylesheet()
 		);
 		$this->assertEquals(
-			'body{color: var(--wp--preset--color--grey);}.wp-site-blocks > * + * { margin-top: var( --wp--style--block-gap ); margin-bottom: 0; }a{color: #111;}h1{font-size: 1em;}h2{font-size: 2em;}.wp-block-group{padding-top: 12px;padding-bottom: 24px;}.wp-block-group a{color: #333;}h1 a,h2 a,h3 a,h4 a,h5 a,h6 a{color: #222;}.wp-block-post-title{font-size: 5em;}.wp-block-post-title a{color: #555;}.wp-block-query-title{font-size: 5em;}.wp-block-query-title a{color: #555;}.has-grey-color{color: var(--wp--preset--color--grey) !important;}.has-grey-background-color{background-color: var(--wp--preset--color--grey) !important;}.has-grey-border-color{border-color: var(--wp--preset--color--grey) !important;}',
+			'body{color: var(--wp--preset--color--grey);}a{color: #111;}h1{font-size: 1em;}h2{font-size: 2em;}.wp-block-group{padding-top: 12px;padding-bottom: 24px;}.wp-block-group a{color: #333;}h1 a,h2 a,h3 a,h4 a,h5 a,h6 a{color: #222;}.wp-block-post-title{font-size: 5em;}.wp-block-post-title a{color: #555;}.wp-block-query-title{font-size: 5em;}.wp-block-query-title a{color: #555;}.has-grey-color{color: var(--wp--preset--color--grey) !important;}.has-grey-background-color{background-color: var(--wp--preset--color--grey) !important;}.has-grey-border-color{border-color: var(--wp--preset--color--grey) !important;}',
 			$theme_json->get_stylesheet( 'block_styles' )
 		);
 		$this->assertEquals(
diff --git a/phpunit/class-wp-theme-json-test.php b/phpunit/class-wp-theme-json-test.php
index 5fde40de86e7cb..d88adc7f384a3e 100644
--- a/phpunit/class-wp-theme-json-test.php
+++ b/phpunit/class-wp-theme-json-test.php
@@ -225,11 +225,11 @@ function test_get_stylesheet_support_for_shorthand_and_longhand_values() {
 		);
 
 		$this->assertEquals(
-			'.wp-site-blocks > * + * { margin-top: var( --wp--style--block-gap ); margin-bottom: 0; }.wp-block-group{border-radius: 10px;margin: 1em;padding: 24px;}.wp-block-image{border-top-left-radius: 10px;border-bottom-right-radius: 1em;margin-bottom: 30px;padding-top: 15px;}',
+			'.wp-block-group{border-radius: 10px;margin: 1em;padding: 24px;}.wp-block-image{border-top-left-radius: 10px;border-bottom-right-radius: 1em;margin-bottom: 30px;padding-top: 15px;}',
 			$theme_json->get_stylesheet()
 		);
 		$this->assertEquals(
-			'.wp-site-blocks > * + * { margin-top: var( --wp--style--block-gap ); margin-bottom: 0; }.wp-block-group{border-radius: 10px;margin: 1em;padding: 24px;}.wp-block-image{border-top-left-radius: 10px;border-bottom-right-radius: 1em;margin-bottom: 30px;padding-top: 15px;}',
+			'.wp-block-group{border-radius: 10px;margin: 1em;padding: 24px;}.wp-block-image{border-top-left-radius: 10px;border-bottom-right-radius: 1em;margin-bottom: 30px;padding-top: 15px;}',
 			$theme_json->get_stylesheet( 'block_styles' )
 		);
 	}
@@ -260,6 +260,9 @@ function test_get_stylesheet() {
 							),
 						),
 					),
+					'spacing'    => array(
+						'blockGap' => false,
+					),
 					'misc'       => 'value',
 					'blocks'     => array(
 						'core/group' => array(
@@ -423,11 +426,11 @@ function test_get_stylesheet_preset_rules_come_after_block_rules() {
 		);
 
 		$this->assertEquals(
-			'.wp-block-group{--wp--preset--color--grey: grey;}.wp-site-blocks > * + * { margin-top: var( --wp--style--block-gap ); margin-bottom: 0; }.wp-block-group{color: red;}.wp-block-group.has-grey-color{color: var(--wp--preset--color--grey) !important;}.wp-block-group.has-grey-background-color{background-color: var(--wp--preset--color--grey) !important;}.wp-block-group.has-grey-border-color{border-color: var(--wp--preset--color--grey) !important;}',
+			'.wp-block-group{--wp--preset--color--grey: grey;}.wp-block-group{color: red;}.wp-block-group.has-grey-color{color: var(--wp--preset--color--grey) !important;}.wp-block-group.has-grey-background-color{background-color: var(--wp--preset--color--grey) !important;}.wp-block-group.has-grey-border-color{border-color: var(--wp--preset--color--grey) !important;}',
 			$theme_json->get_stylesheet()
 		);
 		$this->assertEquals(
-			'.wp-site-blocks > * + * { margin-top: var( --wp--style--block-gap ); margin-bottom: 0; }.wp-block-group{color: red;}.wp-block-group.has-grey-color{color: var(--wp--preset--color--grey) !important;}.wp-block-group.has-grey-background-color{background-color: var(--wp--preset--color--grey) !important;}.wp-block-group.has-grey-border-color{border-color: var(--wp--preset--color--grey) !important;}',
+			'.wp-block-group{color: red;}.wp-block-group.has-grey-color{color: var(--wp--preset--color--grey) !important;}.wp-block-group.has-grey-background-color{background-color: var(--wp--preset--color--grey) !important;}.wp-block-group.has-grey-border-color{border-color: var(--wp--preset--color--grey) !important;}',
 			$theme_json->get_stylesheet( 'block_styles' )
 		);
 	}
@@ -465,7 +468,7 @@ public function test_get_stylesheet_preset_values_are_marked_as_important() {
 		);
 
 		$this->assertEquals(
-			'body{--wp--preset--color--grey: grey;}.wp-site-blocks > * + * { margin-top: var( --wp--style--block-gap ); margin-bottom: 0; }p{background-color: blue;color: red;font-size: 12px;line-height: 1.3;}.has-grey-color{color: var(--wp--preset--color--grey) !important;}.has-grey-background-color{background-color: var(--wp--preset--color--grey) !important;}.has-grey-border-color{border-color: var(--wp--preset--color--grey) !important;}',
+			'body{--wp--preset--color--grey: grey;}p{background-color: blue;color: red;font-size: 12px;line-height: 1.3;}.has-grey-color{color: var(--wp--preset--color--grey) !important;}.has-grey-background-color{background-color: var(--wp--preset--color--grey) !important;}.has-grey-border-color{border-color: var(--wp--preset--color--grey) !important;}',
 			$theme_json->get_stylesheet()
 		);
 	}