diff --git a/src/wp-includes/block-editor.php b/src/wp-includes/block-editor.php
index 2977afbeb8cb9..3cde142c641cb 100644
--- a/src/wp-includes/block-editor.php
+++ b/src/wp-includes/block-editor.php
@@ -488,7 +488,7 @@ function get_block_editor_settings( array $custom_settings, $block_editor_contex
 		unset( $editor_settings['__experimentalFeatures']['spacing']['padding'] );
 	}
 	if ( isset( $editor_settings['__experimentalFeatures']['spacing']['customSpacingSize'] ) ) {
-		$editor_settings['disableCustomSpacingSizes'] = ! $editor_ettings['__experimentalFeatures']['spacing']['customSpacingSize'];
+		$editor_settings['disableCustomSpacingSizes'] = ! $editor_settings['__experimentalFeatures']['spacing']['customSpacingSize'];
 		unset( $editor_settings['__experimentalFeatures']['spacing']['customSpacingSize'] );
 	}
 
diff --git a/src/wp-includes/class-wp-theme-json-resolver.php b/src/wp-includes/class-wp-theme-json-resolver.php
index 5d0dd099c20e5..74a0cd1daa0d9 100644
--- a/src/wp-includes/class-wp-theme-json-resolver.php
+++ b/src/wp-includes/class-wp-theme-json-resolver.php
@@ -418,7 +418,7 @@ public static function get_user_data() {
 	 * @since 5.8.0
 	 * @since 5.9.0 Added user data, removed the `$settings` parameter,
 	 *              added the `$origin` parameter.
-	 * @since 6.1.0 Added block data.
+	 * @since 6.1.0 Added block data and generation of spacingSizes array.
 	 *
 	 * @param string $origin Optional. To what level should we merge data.
 	 *                       Valid values are 'theme' or 'custom'. Default 'custom'.
@@ -438,6 +438,9 @@ public static function get_merged_data( $origin = 'custom' ) {
 			$result->merge( static::get_user_data() );
 		}
 
+		// Generate the default spacingSizes array based on the merged spacingScale settings.
+		$result->set_spacing_sizes();
+
 		return $result;
 	}
 
diff --git a/src/wp-includes/class-wp-theme-json.php b/src/wp-includes/class-wp-theme-json.php
index 4e7c704cce16b..752cbee00d96a 100644
--- a/src/wp-includes/class-wp-theme-json.php
+++ b/src/wp-includes/class-wp-theme-json.php
@@ -164,6 +164,24 @@ class WP_Theme_JSON {
 			'classes'           => array( '.has-$slug-font-family' => 'font-family' ),
 			'properties'        => array( 'font-family' ),
 		),
+		array(
+			'path'              => array( 'spacing', 'spacingSizes' ),
+			'prevent_override'  => false,
+			'use_default_names' => true,
+			'value_key'         => 'size',
+			'css_vars'          => '--wp--preset--spacing--$slug',
+			'classes'           => array(),
+			'properties'        => array( 'padding', 'margin' ),
+		),
+		array(
+			'path'              => array( 'spacing', 'spacingScale' ),
+			'prevent_override'  => false,
+			'use_default_names' => true,
+			'value_key'         => 'size',
+			'css_vars'          => '--wp--preset--spacing--$slug',
+			'classes'           => array(),
+			'properties'        => array( 'padding', 'margin' ),
+		),
 	);
 
 	/**
@@ -307,10 +325,13 @@ class WP_Theme_JSON {
 			'wideSize'    => null,
 		),
 		'spacing'                       => array(
-			'blockGap' => null,
-			'margin'   => null,
-			'padding'  => null,
-			'units'    => null,
+			'customSpacingSize' => null,
+			'spacingSizes'      => null,
+			'spacingScale'      => null,
+			'blockGap'          => null,
+			'margin'            => null,
+			'padding'           => null,
+			'units'             => null,
 		),
 		'typography'                    => array(
 			'customFontSize' => null,
@@ -2886,4 +2907,122 @@ public function get_data() {
 		return $output;
 	}
 
+	/**
+	 * Sets the spacingSizes array based on the spacingScale values from theme.json.
+	 *
+	 * @since 6.1.0
+	 *
+	 * @return null|void
+	 */
+	public function set_spacing_sizes() {
+		$spacing_scale = _wp_array_get( $this->theme_json, array( 'settings', 'spacing', 'spacingScale' ), array() );
+
+		if ( ! is_numeric( $spacing_scale['steps'] )
+			|| ! isset( $spacing_scale['mediumStep'] )
+			|| ! isset( $spacing_scale['unit'] )
+			|| ! isset( $spacing_scale['operator'] )
+			|| ! isset( $spacing_scale['increment'] )
+			|| ! isset( $spacing_scale['steps'] )
+			|| ! is_numeric( $spacing_scale['increment'] )
+			|| ! is_numeric( $spacing_scale['mediumStep'] )
+			|| ( '+' !== $spacing_scale['operator'] && '*' !== $spacing_scale['operator'] ) ) {
+			if ( ! empty( $spacing_scale ) ) {
+				trigger_error( __( 'Some of the theme.json settings.spacing.spacingScale values are invalid' ), E_USER_NOTICE );
+			}
+			return null;
+		}
+
+		// If theme authors want to prevent the generation of the core spacing scale they can set their theme.json spacingScale.steps to 0.
+		if ( 0 === $spacing_scale['steps'] ) {
+			return null;
+		}
+
+		$unit            = '%' === $spacing_scale['unit'] ? '%' : sanitize_title( $spacing_scale['unit'] );
+		$current_step    = $spacing_scale['mediumStep'];
+		$steps_mid_point = round( $spacing_scale['steps'] / 2, 0 );
+		$x_small_count   = null;
+		$below_sizes     = array();
+		$slug            = 40;
+		$remainder       = 0;
+
+		for ( $below_midpoint_count = $steps_mid_point - 1; $spacing_scale['steps'] > 1 && $slug > 0 && $below_midpoint_count > 0; $below_midpoint_count-- ) {
+			if ( '+' === $spacing_scale['operator'] ) {
+				$current_step -= $spacing_scale['increment'];
+			} elseif ( $spacing_scale['increment'] > 1 ) {
+				$current_step /= $spacing_scale['increment'];
+			} else {
+				$current_step *= $spacing_scale['increment'];
+			}
+
+			if ( $current_step <= 0 ) {
+				$remainder = $below_midpoint_count;
+				break;
+			}
+
+			$below_sizes[] = array(
+				/* translators: %s: Digit to indicate multiple of sizing, eg. 2X-Small. */
+				'name' => $below_midpoint_count === $steps_mid_point - 1 ? __( 'Small' ) : sprintf( __( '%sX-Small' ), (string) $x_small_count ),
+				'slug' => (string) $slug,
+				'size' => round( $current_step, 2 ) . $unit,
+			);
+
+			if ( $below_midpoint_count === $steps_mid_point - 2 ) {
+				$x_small_count = 2;
+			}
+
+			if ( $below_midpoint_count < $steps_mid_point - 2 ) {
+				$x_small_count++;
+			}
+
+			$slug -= 10;
+		}
+
+		$below_sizes = array_reverse( $below_sizes );
+
+		$below_sizes[] = array(
+			'name' => __( 'Medium' ),
+			'slug' => '50',
+			'size' => $spacing_scale['mediumStep'] . $unit,
+		);
+
+		$current_step  = $spacing_scale['mediumStep'];
+		$x_large_count = null;
+		$above_sizes   = array();
+		$slug          = 60;
+		$steps_above   = ( $spacing_scale['steps'] - $steps_mid_point ) + $remainder;
+
+		for ( $above_midpoint_count = 0; $above_midpoint_count < $steps_above; $above_midpoint_count++ ) {
+			$current_step = '+' === $spacing_scale['operator']
+				? $current_step + $spacing_scale['increment']
+				: ( $spacing_scale['increment'] >= 1 ? $current_step * $spacing_scale['increment'] : $current_step / $spacing_scale['increment'] );
+
+			$above_sizes[] = array(
+				/* translators: %s: Digit to indicate multiple of sizing, eg. 2X-Large. */
+				'name' => 0 === $above_midpoint_count ? __( 'Large' ) : sprintf( __( '%sX-Large' ), (string) $x_large_count ),
+				'slug' => (string) $slug,
+				'size' => round( $current_step, 2 ) . $unit,
+			);
+
+			if ( 1 === $above_midpoint_count ) {
+				$x_large_count = 2;
+			}
+
+			if ( $above_midpoint_count > 1 ) {
+				$x_large_count++;
+			}
+
+			$slug += 10;
+		}
+
+		$spacing_sizes = array_merge( $below_sizes, $above_sizes );
+
+		// If there are 7 or less steps in the scale revert to numbers for labels instead of t-shirt sizes.
+		if ( $spacing_scale['steps'] <= 7 ) {
+			for ( $spacing_sizes_count = 0; $spacing_sizes_count < count( $spacing_sizes ); $spacing_sizes_count++ ) {
+				$spacing_sizes[ $spacing_sizes_count ]['name'] = (string) ( $spacing_sizes_count + 1 );
+			}
+		}
+
+		_wp_array_set( $this->theme_json, array( 'settings', 'spacing', 'spacingSizes', 'default' ), $spacing_sizes );
+	}
 }
diff --git a/src/wp-includes/theme-i18n.json b/src/wp-includes/theme-i18n.json
index f5a65dbddc37d..82f89bd3d282f 100644
--- a/src/wp-includes/theme-i18n.json
+++ b/src/wp-includes/theme-i18n.json
@@ -30,6 +30,13 @@
 					}
 				]
 		},
+		"spacing": {
+			"spacingSizes": [
+				{
+					"name": "Space size name"
+				}
+			]
+		},
 		"blocks": {
 			"*": {
 				"typography": {
@@ -55,6 +62,13 @@
 							"name": "Gradient name"
 						}
 					]
+				},
+				"spacing": {
+					"spacingSizes": [
+						{
+							"name": "Space size name"
+						}
+					]
 				}
 			}
 		}
diff --git a/tests/phpunit/tests/theme/wpThemeJson.php b/tests/phpunit/tests/theme/wpThemeJson.php
index f1e3e1ae8b9c1..d67b5872b91c2 100644
--- a/tests/phpunit/tests/theme/wpThemeJson.php
+++ b/tests/phpunit/tests/theme/wpThemeJson.php
@@ -3493,4 +3493,385 @@ function test_get_styles_for_block_with_content_width() {
 		$style_rules = $theme_json->get_styles_for_block( $metadata );
 		$this->assertSame( $expected, $root_rules . $style_rules );
 	}
+
+	/**
+	 * Tests generating the spacing presets array based on the spacing scale provided.
+	 *
+	 * @ticket 56467
+	 *
+	 * @dataProvider data_generate_spacing_scale_fixtures
+	 *
+	 * @param array $spacing_scale   Example spacing scale definitions from the data provider.
+	 * @param array $expected_output Expected output from data provider.
+	 */
+	function test_should_set_spacing_sizes( $spacing_scale, $expected_output ) {
+		$theme_json = new WP_Theme_JSON(
+			array(
+				'version'  => 2,
+				'settings' => array(
+					'spacing' => array(
+						'spacingScale' => $spacing_scale,
+					),
+				),
+			)
+		);
+
+		$theme_json->set_spacing_sizes();
+		$this->assertSame( $expected_output, _wp_array_get( $theme_json->get_raw_data(), array( 'settings', 'spacing', 'spacingSizes', 'default' ) ) );
+	}
+
+	/**
+	 * Data provider for spacing scale tests.
+	 *
+	 * @ticket 56467
+	 *
+	 * @return array
+	 */
+	function data_generate_spacing_scale_fixtures() {
+		return array(
+			'only one value when single step in spacing scale' => array(
+				'spacing_scale'   => array(
+					'operator'   => '+',
+					'increment'  => 1.5,
+					'steps'      => 1,
+					'mediumStep' => 4,
+					'unit'       => 'rem',
+				),
+				'expected_output' => array(
+					array(
+						'name' => '1',
+						'slug' => '50',
+						'size' => '4rem',
+					),
+				),
+			),
+			'one step above medium when two steps in spacing scale' => array(
+				'spacing_scale'   => array(
+					'operator'   => '+',
+					'increment'  => 1.5,
+					'steps'      => 2,
+					'mediumStep' => 4,
+					'unit'       => 'rem',
+				),
+				'expected_output' => array(
+					array(
+						'name' => '1',
+						'slug' => '50',
+						'size' => '4rem',
+					),
+					array(
+						'name' => '2',
+						'slug' => '60',
+						'size' => '5.5rem',
+					),
+				),
+			),
+			'one step above medium and one below when three steps in spacing scale' => array(
+				'spacing_scale'   => array(
+					'operator'   => '+',
+					'increment'  => 1.5,
+					'steps'      => 3,
+					'mediumStep' => 4,
+					'unit'       => 'rem',
+				),
+				'expected_output' => array(
+					array(
+						'name' => '1',
+						'slug' => '40',
+						'size' => '2.5rem',
+					),
+					array(
+						'name' => '2',
+						'slug' => '50',
+						'size' => '4rem',
+					),
+					array(
+						'name' => '3',
+						'slug' => '60',
+						'size' => '5.5rem',
+					),
+				),
+			),
+			'extra step added above medium when an even number of steps > 2 specified' => array(
+				'spacing_scale'   => array(
+					'operator'   => '+',
+					'increment'  => 1.5,
+					'steps'      => 4,
+					'mediumStep' => 4,
+					'unit'       => 'rem',
+				),
+				'expected_output' => array(
+					array(
+						'name' => '1',
+						'slug' => '40',
+						'size' => '2.5rem',
+					),
+					array(
+						'name' => '2',
+						'slug' => '50',
+						'size' => '4rem',
+					),
+					array(
+						'name' => '3',
+						'slug' => '60',
+						'size' => '5.5rem',
+					),
+					array(
+						'name' => '4',
+						'slug' => '70',
+						'size' => '7rem',
+					),
+				),
+			),
+			'extra steps above medium if bottom end will go below zero' => array(
+				'spacing_scale'   => array(
+					'operator'   => '+',
+					'increment'  => 2.5,
+					'steps'      => 5,
+					'mediumStep' => 5,
+					'unit'       => 'rem',
+				),
+				'expected_output' => array(
+					array(
+						'name' => '1',
+						'slug' => '40',
+						'size' => '2.5rem',
+					),
+					array(
+						'name' => '2',
+						'slug' => '50',
+						'size' => '5rem',
+					),
+					array(
+						'name' => '3',
+						'slug' => '60',
+						'size' => '7.5rem',
+					),
+					array(
+						'name' => '4',
+						'slug' => '70',
+						'size' => '10rem',
+					),
+					array(
+						'name' => '5',
+						'slug' => '80',
+						'size' => '12.5rem',
+					),
+				),
+			),
+			'multiplier correctly calculated above and below medium' => array(
+				'spacing_scale'   => array(
+					'operator'   => '*',
+					'increment'  => 1.5,
+					'steps'      => 5,
+					'mediumStep' => 1.5,
+					'unit'       => 'rem',
+				),
+				'expected_output' => array(
+					array(
+						'name' => '1',
+						'slug' => '30',
+						'size' => '0.67rem',
+					),
+					array(
+						'name' => '2',
+						'slug' => '40',
+						'size' => '1rem',
+					),
+					array(
+						'name' => '3',
+						'slug' => '50',
+						'size' => '1.5rem',
+					),
+					array(
+						'name' => '4',
+						'slug' => '60',
+						'size' => '2.25rem',
+					),
+					array(
+						'name' => '5',
+						'slug' => '70',
+						'size' => '3.38rem',
+					),
+				),
+			),
+			'increment < 1 combined showing * operator acting as divisor above and below medium' => array(
+				'spacing_scale'   => array(
+					'operator'   => '*',
+					'increment'  => 0.25,
+					'steps'      => 5,
+					'mediumStep' => 1.5,
+					'unit'       => 'rem',
+				),
+				'expected_output' => array(
+					array(
+						'name' => '1',
+						'slug' => '30',
+						'size' => '0.09rem',
+					),
+					array(
+						'name' => '2',
+						'slug' => '40',
+						'size' => '0.38rem',
+					),
+					array(
+						'name' => '3',
+						'slug' => '50',
+						'size' => '1.5rem',
+					),
+					array(
+						'name' => '4',
+						'slug' => '60',
+						'size' => '6rem',
+					),
+					array(
+						'name' => '5',
+						'slug' => '70',
+						'size' => '24rem',
+					),
+				),
+			),
+			't-shirt sizing used if more than 7 steps in scale' => array(
+				'spacing_scale'   => array(
+					'operator'   => '*',
+					'increment'  => 1.5,
+					'steps'      => 8,
+					'mediumStep' => 1.5,
+					'unit'       => 'rem',
+				),
+				'expected_output' => array(
+					array(
+						'name' => '2X-Small',
+						'slug' => '20',
+						'size' => '0.44rem',
+					),
+					array(
+						'name' => 'X-Small',
+						'slug' => '30',
+						'size' => '0.67rem',
+					),
+					array(
+						'name' => 'Small',
+						'slug' => '40',
+						'size' => '1rem',
+					),
+					array(
+						'name' => 'Medium',
+						'slug' => '50',
+						'size' => '1.5rem',
+					),
+					array(
+						'name' => 'Large',
+						'slug' => '60',
+						'size' => '2.25rem',
+					),
+					array(
+						'name' => 'X-Large',
+						'slug' => '70',
+						'size' => '3.38rem',
+					),
+					array(
+						'name' => '2X-Large',
+						'slug' => '80',
+						'size' => '5.06rem',
+					),
+					array(
+						'name' => '3X-Large',
+						'slug' => '90',
+						'size' => '7.59rem',
+					),
+				),
+			),
+		);
+	}
+
+	/**
+	 * Tests generating the spacing presets array based on the spacing scale provided.
+	 *
+	 * @ticket 56467
+	 *
+	 * @dataProvider data_set_spacing_sizes_when_invalid
+	 *
+	 * @param array $spacing_scale   Example spacing scale definitions from the data provider.
+	 * @param array $expected_output Expected output from data provider.
+	 */
+	public function test_set_spacing_sizes_should_detect_invalid_spacing_scale( $spacing_scale, $expected_output ) {
+		$this->expectNotice();
+		$this->expectNoticeMessage( 'Some of the theme.json settings.spacing.spacingScale values are invalid' );
+
+		$theme_json = new WP_Theme_JSON(
+			array(
+				'version'  => 2,
+				'settings' => array(
+					'spacing' => array(
+						'spacingScale' => $spacing_scale,
+					),
+				),
+			)
+		);
+
+		$theme_json->set_spacing_sizes();
+		$this->assertSame( $expected_output, _wp_array_get( $theme_json->get_raw_data(), array( 'settings', 'spacing', 'spacingSizes', 'default' ) ) );
+	}
+
+	/**
+	 * Data provider for spacing scale tests.
+	 *
+	 * @ticket 56467
+	 *
+	 * @return array
+	 */
+	function data_set_spacing_sizes_when_invalid() {
+		return array(
+			'missing operator value'  => array(
+				'spacing_scale'   => array(
+					'operator'   => '',
+					'increment'  => 1.5,
+					'steps'      => 1,
+					'mediumStep' => 4,
+					'unit'       => 'rem',
+				),
+				'expected_output' => null,
+			),
+			'non numeric increment'   => array(
+				'spacing_scale'   => array(
+					'operator'   => '+',
+					'increment'  => 'add two to previous value',
+					'steps'      => 1,
+					'mediumStep' => 4,
+					'unit'       => 'rem',
+				),
+				'expected_output' => null,
+			),
+			'non numeric steps'       => array(
+				'spacing_scale'   => array(
+					'operator'   => '+',
+					'increment'  => 1.5,
+					'steps'      => 'spiral staircase preferred',
+					'mediumStep' => 4,
+					'unit'       => 'rem',
+				),
+				'expected_output' => null,
+			),
+			'non numeric medium step' => array(
+				'spacing_scale'   => array(
+					'operator'   => '+',
+					'increment'  => 1.5,
+					'steps'      => 5,
+					'mediumStep' => 'That which is just right',
+					'unit'       => 'rem',
+				),
+				'expected_output' => null,
+			),
+			'missing unit value'      => array(
+				'spacing_scale'   => array(
+					'operator'   => '+',
+					'increment'  => 1.5,
+					'steps'      => 5,
+					'mediumStep' => 4,
+				),
+				'expected_output' => null,
+			),
+		);
+	}
 }