diff --git a/amp.php b/amp.php
index 0cfba95132e..036c368fc18 100644
--- a/amp.php
+++ b/amp.php
@@ -145,6 +145,7 @@ function amp_init() {
 	add_action( 'admin_init', 'AMP_Options_Manager::register_settings' );
 	add_action( 'wp_loaded', 'amp_editor_core_blocks' );
 	add_action( 'wp_loaded', 'amp_post_meta_box' );
+	add_action( 'wp_loaded', 'amp_editor_core_blocks' );
 	add_action( 'wp_loaded', 'amp_add_options_menu' );
 	add_action( 'parse_query', 'amp_correct_query_when_is_front_page' );
 
diff --git a/assets/css/amp-default.css b/assets/css/amp-default.css
index 0cc0e05da5e..c06e0895dbe 100644
--- a/assets/css/amp-default.css
+++ b/assets/css/amp-default.css
@@ -3,3 +3,13 @@
 	/** Force the image into a box of fixed dimensions and use object-fit to scale. **/
 	object-fit: contain;
 }
+
+.entry__content amp-fit-text blockquote,
+amp-fit-text h1,
+amp-fit-text h2,
+amp-fit-text h3,
+amp-fit-text h4,
+amp-fit-text h5,
+amp-fit-text h6 {
+	font-size: inherit;
+}
\ No newline at end of file
diff --git a/assets/css/amp-editor-blocks.css b/assets/css/amp-editor-blocks.css
new file mode 100644
index 00000000000..e16b21b8c22
--- /dev/null
+++ b/assets/css/amp-editor-blocks.css
@@ -0,0 +1,4 @@
+.is-amp-fit-text + .blocks-font-size > .components-font-size-picker__buttons,
+.is-amp-fit-text + .blocks-font-size > .components-font-size-picker__custom-input {
+    display: none;
+}
diff --git a/assets/js/amp-editor-blocks.js b/assets/js/amp-editor-blocks.js
index 2be3f238ef9..4dc2b106bb2 100644
--- a/assets/js/amp-editor-blocks.js
+++ b/assets/js/amp-editor-blocks.js
@@ -85,7 +85,19 @@ var ampEditorBlocks = ( function() { // eslint-disable-line no-unused-vars
 				'core/image',
 				'core/video',
 				'core/audio'
-			]
+			],
+			textBlocks: [
+				'core/paragraph',
+				'core/heading',
+				'core/code',
+				'core/quote',
+				'core/subhead'
+			],
+			ampSettingsLabel: __( 'AMP Settings' ),
+			fontSizes: {
+				small: 14,
+				larger: 48
+			}
 		}
 	};
 
@@ -178,6 +190,38 @@ var ampEditorBlocks = ( function() { // eslint-disable-line no-unused-vars
 			};
 		}
 
+		// Fit-text for text blocks.
+		if ( -1 !== component.data.textBlocks.indexOf( name ) ) {
+			if ( ! settings.attributes ) {
+				settings.attributes = {};
+			}
+			settings.attributes.ampFitText = {
+				type: 'boolean',
+				default: false
+			};
+			settings.attributes.minFont = {
+				type: 'number',
+				default: component.data.fontSizes.small,
+				source: 'attribute',
+				selector: 'amp-fit-text',
+				attribute: 'min-font-size'
+			};
+			settings.attributes.maxFont = {
+				type: 'number',
+				default: component.data.fontSizes.larger,
+				source: 'attribute',
+				selector: 'amp-fit-text',
+				attribute: 'max-font-size'
+			};
+			settings.attributes.height = {
+				type: 'number',
+				default: 50,
+				source: 'attribute',
+				selector: 'amp-fit-text',
+				attribute: 'height'
+			};
+		}
+
 		// Layout settings for embeds and media blocks.
 		if ( 0 === name.indexOf( 'core-embed' ) || -1 !== component.data.mediaBlocks.indexOf( name ) ) {
 			if ( ! settings.attributes ) {
@@ -222,6 +266,8 @@ var ampEditorBlocks = ( function() { // eslint-disable-line no-unused-vars
 				}
 			} else if ( -1 !== component.data.mediaBlocks.indexOf( name ) || 0 === name.indexOf( 'core-embed/' ) ) {
 				inspectorControls = component.setUpInspectorControls( props );
+			} else if ( -1 !== component.data.textBlocks.indexOf( name ) ) {
+				inspectorControls = component.setUpTextBlocksInspectorControls( props );
 			}
 
 			// Return just inspector controls in case of 'nodisplay'.
@@ -314,6 +360,135 @@ var ampEditorBlocks = ( function() { // eslint-disable-line no-unused-vars
 		);
 	};
 
+	/**
+	 * Setup inspector controls for text blocks.
+	 *
+	 * @todo Consider wrapping the render function to delete the original font size in text settings when ampFitText.
+	 *
+	 * @param {Object} props Props.
+	 * @return {Object|Element|*|{$$typeof, type, key, ref, props, _owner}} Inspector Controls.
+	 */
+	component.setUpTextBlocksInspectorControls = function setUpInspectorControls( props ) {
+		var inspectorPanelBodyArgs,
+			ampFitText = props.attributes.ampFitText,
+			minFont = props.attributes.minFont,
+			maxFont = props.attributes.maxFont,
+			height = props.attributes.height,
+			isSelected = props.isSelected,
+			el = wp.element.createElement,
+			InspectorControls = wp.editor.InspectorControls,
+			TextControl = wp.components.TextControl,
+			FontSizePicker = wp.components.FontSizePicker,
+			ToggleControl = wp.components.ToggleControl,
+			PanelBody = wp.components.PanelBody,
+			label = __( 'Use AMP Fit Text' ),
+			FONT_SIZES = [
+				{
+					name: 'small',
+					shortName: __( 'S' ),
+					size: 14
+				},
+				{
+					name: 'regular',
+					shortName: __( 'M' ),
+					size: 16
+				},
+				{
+					name: 'large',
+					shortName: __( 'L' ),
+					size: 36
+				},
+				{
+					name: 'larger',
+					shortName: __( 'XL' ),
+					size: 48
+				}
+			];
+
+		if ( ! isSelected ) {
+			return null;
+		}
+
+		inspectorPanelBodyArgs = [
+			PanelBody,
+			{ title: component.data.ampSettingsLabel, className: ampFitText ? 'is-amp-fit-text' : '' },
+			el( ToggleControl, {
+				label: label,
+				checked: ampFitText,
+				onChange: function() {
+					props.setAttributes( { ampFitText: ! ampFitText } );
+				}
+			} )
+		];
+
+		if ( ampFitText ) {
+			inspectorPanelBodyArgs.push.apply( inspectorPanelBodyArgs, [
+				el( TextControl, {
+					label: __( 'Height' ),
+					value: height,
+					type: 'number',
+					min: 1,
+					onChange: function( nextHeight ) {
+						props.setAttributes( { height: nextHeight } );
+					}
+				} ),
+				maxFont > height && el(
+					wp.components.Notice,
+					{
+						status: 'error',
+						isDismissible: false
+					},
+					__( 'The height must be greater than the max font size.' )
+				),
+				el( PanelBody, { title: __( 'Minimum font size' ) },
+					el( FontSizePicker, {
+						fallbackFontSize: 14,
+						value: minFont,
+						fontSizes: FONT_SIZES,
+						onChange: function( nextMinFont ) {
+							if ( ! nextMinFont ) {
+								nextMinFont = component.data.fontSizes.small; // @todo Supplying fallbackFontSize should be done automatically by the component?
+							}
+							if ( nextMinFont <= maxFont ) {
+								props.setAttributes( { minFont: nextMinFont } );
+							}
+						}
+					} )
+				),
+				minFont > maxFont && el(
+					wp.components.Notice,
+					{
+						status: 'error',
+						isDismissible: false
+					},
+					__( 'The min font size must less than the max font size.' )
+				),
+				el( PanelBody, { title: __( 'Maximum font size' ) },
+					el( FontSizePicker, {
+						value: maxFont,
+						fallbackFontSize: 48,
+						fontSizes: FONT_SIZES,
+						onChange: function( nextMaxFont ) {
+							if ( ! nextMaxFont ) {
+								nextMaxFont = component.data.fontSizes.larger; // @todo Supplying fallbackFontSize should be done automatically by the component?
+							}
+							props.setAttributes( {
+								maxFont: nextMaxFont,
+								height: Math.max( nextMaxFont, height )
+							} );
+						}
+					} )
+				)
+			] );
+		}
+
+		return (
+			el( InspectorControls, { key: 'inspector' },
+				el.apply( null, inspectorPanelBodyArgs )
+			)
+		);
+	};
+
 	/**
 	 * Set up inspector controls for shortcode block.
 	 * Adds ampCarousel attribute in case of gallery shortcode.
@@ -325,7 +500,7 @@ var ampEditorBlocks = ( function() { // eslint-disable-line no-unused-vars
 		var ampCarousel = props.attributes.ampCarousel,
 			isSelected = props.isSelected,
 			el = wp.element.createElement,
-			InspectorControls = wp.blocks.InspectorControls,
+			InspectorControls = wp.editor.InspectorControls,
 			ToggleControl = wp.components.ToggleControl,
 			PanelBody = wp.components.PanelBody,
 			toggleControl;
@@ -359,7 +534,12 @@ var ampEditorBlocks = ( function() { // eslint-disable-line no-unused-vars
 	 * @return {*} Output element.
 	 */
 	component.filterBlocksSave = function filterBlocksSave( element, blockType, attributes ) {
-		var text;
+		var text,
+			fitTextProps = {
+				layout: 'fixed-height',
+				children: element
+			};
+
 		if ( 'core/shortcode' === blockType.name && component.isGalleryShortcode( attributes ) ) {
 			if ( attributes.ampCarousel ) {
 				// If the text contains amp-carousel, lets remove it.
@@ -390,6 +570,17 @@ var ampEditorBlocks = ( function() { // eslint-disable-line no-unused-vars
 				{},
 				text
 			);
+		} else if ( -1 !== component.data.textBlocks.indexOf( blockType.name ) && attributes.ampFitText ) {
+			if ( attributes.minFont ) {
+				fitTextProps[ 'min-font-size' ] = attributes.minFont;
+			}
+			if ( attributes.maxFont ) {
+				fitTextProps[ 'max-font-size' ] = attributes.maxFont;
+			}
+			if ( attributes.height ) {
+				fitTextProps.height = attributes.height;
+			}
+			return wp.element.createElement( 'amp-fit-text', fitTextProps );
 		}
 		return element;
 	};
diff --git a/includes/admin/class-amp-editor-blocks.php b/includes/admin/class-amp-editor-blocks.php
index b847e2362fd..5dfa5bde558 100644
--- a/includes/admin/class-amp-editor-blocks.php
+++ b/includes/admin/class-amp-editor-blocks.php
@@ -11,6 +11,30 @@
  */
 class AMP_Editor_Blocks {
 
+	/**
+	 * List of AMP scripts that need to be printed when AMP components are used in non-AMP document context ("dirty AMP").
+	 *
+	 * @var array
+	 */
+	public $content_required_amp_scripts = array();
+
+	/**
+	 * AMP components that have blocks.
+	 *
+	 * @var array
+	 */
+	public $amp_blocks = array(
+		'amp-mathml',
+		'amp-o2-player',
+		'amp-ooyala-player',
+		'amp-reach-player',
+		'amp-springboard-player',
+		'amp-jwplayer',
+		'amp-brid-player',
+		'amp-ima-video',
+		'amp-fit-text',
+	);
+
 	/**
 	 * Init.
 	 */
@@ -18,6 +42,8 @@ public function init() {
 		if ( function_exists( 'gutenberg_init' ) ) {
 			add_action( 'enqueue_block_editor_assets', array( $this, 'enqueue_block_editor_assets' ) );
 			add_filter( 'wp_kses_allowed_html', array( $this, 'whitelist_block_atts_in_wp_kses_allowed_html' ), 10, 2 );
+			add_filter( 'the_content', array( $this, 'tally_content_requiring_amp_scripts' ) );
+			add_action( 'wp_print_footer_scripts', array( $this, 'print_dirty_amp_scripts' ) );
 		}
 	}
 
@@ -40,18 +66,7 @@ public function whitelist_block_atts_in_wp_kses_allowed_html( $tags, $context )
 			$tag['data-amp-noloading'] = true;
 		}
 
-		$amp_blocks = array(
-			'amp-mathml',
-			'amp-o2-player',
-			'amp-ooyala-player',
-			'amp-reach-player',
-			'amp-springboard-player',
-			'amp-jwplayer',
-			'amp-brid-player',
-			'amp-ima-video',
-		);
-
-		foreach ( $amp_blocks as $amp_block ) {
+		foreach ( $this->amp_blocks as $amp_block ) {
 			if ( ! isset( $tags[ $amp_block ] ) ) {
 				$tags[ $amp_block ] = array();
 			}
@@ -62,6 +77,7 @@ public function whitelist_block_atts_in_wp_kses_allowed_html( $tags, $context )
 						'layout',
 						'width',
 						'height',
+						'class',
 					),
 					true
 				),
@@ -89,6 +105,14 @@ public function whitelist_block_atts_in_wp_kses_allowed_html( $tags, $context )
 	 */
 	public function enqueue_block_editor_assets() {
 
+		// Styles.
+		wp_enqueue_style(
+			'amp-editor-blocks-style',
+			amp_get_asset_url( 'css/amp-editor-blocks.css' ),
+			array(),
+			AMP__VERSION
+		);
+
 		// Scripts.
 		wp_enqueue_script(
 			'amp-editor-blocks-build',
@@ -107,4 +131,32 @@ public function enqueue_block_editor_assets() {
 
 		wp_add_inline_script( 'amp-editor-blocks', sprintf( 'ampEditorBlocks.boot();' ) );
 	}
+
+	/**
+	 * Tally the AMP component scripts that are needed in a dirty AMP document.
+	 *
+	 * @param string $content Content.
+	 * @return string Content (unmodified).
+	 */
+	public function tally_content_requiring_amp_scripts( $content ) {
+		if ( ! is_amp_endpoint() ) {
+			$pattern = sprintf( '/<(%s)\b.*?>/s', join( '|', $this->amp_blocks ) );
+			if ( preg_match_all( $pattern, $content, $matches ) ) {
+				$this->content_required_amp_scripts = array_merge(
+					$this->content_required_amp_scripts,
+					$matches[1]
+				);
+			}
+		}
+		return $content;
+	}
+
+	/**
+	 * Print AMP scripts required for AMP components used in a non-AMP document (dirty AMP).
+	 */
+	public function print_dirty_amp_scripts() {
+		if ( ! is_amp_endpoint() && ! empty( $this->content_required_amp_scripts ) ) {
+			wp_scripts()->do_items( $this->content_required_amp_scripts );
+		}
+	}
 }