diff --git a/src/wp-includes/class-wp-image-editor-imagick.php b/src/wp-includes/class-wp-image-editor-imagick.php
index f413387233..ee12b401d9 100644
--- a/src/wp-includes/class-wp-image-editor-imagick.php
+++ b/src/wp-includes/class-wp-image-editor-imagick.php
@@ -503,6 +503,10 @@ class WP_Image_Editor_Imagick extends WP_Image_Editor {
 			$size_data['crop'] = false;
 		}
 
+		if ( ( $this->size['width'] == $size_data['width'] ) && ( $this->size['height'] == $size_data['height'] ) ) {
+			return new WP_Error( 'image_subsize_create_error', __( 'The image already has the requested size.' ) );
+		}
+
 		$resized = $this->resize( $size_data['width'], $size_data['height'], $size_data['crop'] );
 
 		if ( is_wp_error( $resized ) ) {
diff --git a/tests/phpunit/tests/media.php b/tests/phpunit/tests/media.php
index 994b4b7c72..fb93d781c3 100644
--- a/tests/phpunit/tests/media.php
+++ b/tests/phpunit/tests/media.php
@@ -3770,6 +3770,40 @@ EOF;
 		}
 	}
 
+	/**
+	 * Test that an image size isn't generated if it matches the original image size.
+	 */
+	public function test_wp_generate_attachment_metadata_doesnt_generate_sizes_for_150_square_image() {
+		$temp_dir = get_temp_dir();
+		$file     = $temp_dir . '/test-square-150.jpg';
+		copy( DIR_TESTDATA . '/images/test-square-150.jpg', $file );
+
+		$attachment_id = self::factory()->attachment->create_object(
+			array(
+				'post_mime_type' => 'image/jpeg',
+				'file'           => $file,
+			)
+		);
+
+		$metadata = wp_generate_attachment_metadata( $attachment_id, $file );
+		$this->assertEquals(
+			array(),
+			$metadata['sizes']
+		);
+		$this->assertEquals(
+			'test-square-150.jpg',
+			basename( $metadata['file'] )
+		);
+		$this->assertEquals(
+			'150',
+			$metadata['width']
+		);
+		$this->assertEquals(
+			'150',
+			$metadata['height']
+		);
+	}
+
 	/**
 	 * Add threshold to create a `-scaled` output image for testing.
 	 */