diff --git a/src/wp-includes/media.php b/src/wp-includes/media.php
index 4657b5872eb18..ef6f61d9143fd 100644
--- a/src/wp-includes/media.php
+++ b/src/wp-includes/media.php
@@ -1153,8 +1153,12 @@ function wp_get_attachment_image( $attachment_id, $size = 'thumbnail', $icon = f
 			unset( $attr['fetchpriority'] );
 		}
 
-		// Generate 'srcset' and 'sizes' if not already present.
-		if ( empty( $attr['srcset'] ) ) {
+		// If srcset is set to false, it should be omitted.
+		if ( isset( $attr['srcset'] ) && false === $attr['srcset'] ) {
+			unset( $attr['srcset'] );
+			unset( $attr['sizes'] );
+		} elseif ( empty( $attr['srcset'] ) ) {
+			// Generate 'srcset' and 'sizes' if not already present and srcset is not set to false.
 			$image_meta = wp_get_attachment_metadata( $attachment_id );
 
 			if ( is_array( $image_meta ) ) {
@@ -1170,6 +1174,12 @@ function wp_get_attachment_image( $attachment_id, $size = 'thumbnail', $icon = f
 					}
 				}
 			}
+
+			// If after trying to generate it, it's still empty, omit it.
+			if ( empty( $attr['srcset'] ) ) {
+				unset( $attr['srcset'] );
+				unset( $attr['sizes'] );
+			}
 		}
 
 		/** This filter is documented in wp-includes/media.php */
diff --git a/tests/phpunit/tests/media/wpGetAttachmentImage.php b/tests/phpunit/tests/media/wpGetAttachmentImage.php
new file mode 100644
index 0000000000000..1ffa30223e033
--- /dev/null
+++ b/tests/phpunit/tests/media/wpGetAttachmentImage.php
@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * @group media
+ */
+class Tests_Media_WpGetAttachmentImage extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 43070
+	 */
+	public function test_wp_get_attachment_image_should_not_include_sizes_when_srcset_is_disabled() {
+		$file          = DIR_TESTDATA . '/images/canola.jpg';
+		$attachment_id = $this->factory->attachment->create_upload_object( $file, 0 );
+
+		$html = wp_get_attachment_image( $attachment_id, 'thumbnail', false, array( 'srcset' => false ) );
+
+		wp_delete_attachment( $attachment_id, true );
+
+		$this->assertStringNotContainsString( 'srcset=', $html, 'The srcset attribute should not be rendered.' );
+		$this->assertStringNotContainsString( 'sizes=', $html, 'The sizes attribute should not be rendered when srcset is absent.' );
+	}
+}