diff --git a/checks/class-wordpress-spelling-check.php b/checks/class-wordpress-spelling-check.php
new file mode 100644
index 00000000..6c14c488
--- /dev/null
+++ b/checks/class-wordpress-spelling-check.php
@@ -0,0 +1,246 @@
+<?php
+/**
+ * Check spelling and capitalization of WordPress.
+ *
+ * @package Theme Check
+ */
+
+// phpcs:disable WordPress.WP.CapitalPDangit -- Intentional lowercase/typo variants are match targets in this checker.
+/**
+ * Check that WordPress is spelled and capitalized correctly in text.
+ *
+ * This check allows lowercase "wordpress" in URL-like contexts and masks
+ * Gutenberg block comments and HTML attribute values to reduce false positives.
+ */
+class WordPress_Spelling_Check implements themecheck {
+	/**
+	 * Error messages, warnings and info notices.
+	 *
+	 * @var array $error
+	 */
+	protected $error = array();
+
+	/**
+	 * Check that return true for good/okay/acceptable, false for bad/not-okay/unacceptable.
+	 *
+	 * @param array $php_files File paths and content for PHP files.
+	 * @param array $css_files File paths and content for CSS files.
+	 * @param array $other_files Folder names, file paths and content for other files.
+	 */
+	public function check( $php_files, $css_files, $other_files ) {
+		$ret = true;
+
+		$files_to_check = array_merge( $php_files, $css_files, $this->filter_other_text_files( $other_files ) );
+
+		foreach ( $files_to_check as $file_path => $file_content ) {
+			checkcount();
+
+			$violation_lines = $this->find_bad_spellings( $file_content );
+			if ( empty( $violation_lines ) ) {
+				continue;
+			}
+
+			$filename = tc_filename( $file_path );
+			$grep     = $this->build_violation_context( $violation_lines );
+
+			$this->error[] = sprintf(
+				'<span class="tc-lead tc-required">%s</span>: %s %s',
+				__( 'REQUIRED', 'theme-check' ),
+				sprintf(
+					__( 'Found incorrect spelling or capitalization of %1$s in the file %2$s. Always use <strong>WordPress</strong> in text.', 'theme-check' ),
+					'<strong>WordPress</strong>',
+					'<strong>' . $filename . '</strong>'
+				),
+				$grep
+			);
+
+			$ret = false;
+		}
+
+		return $ret;
+	}
+
+	/**
+	 * Get error messages from the checks.
+	 *
+	 * @return array Error message.
+	 */
+	public function getError() {
+		return $this->error;
+	}
+
+	/**
+	 * Keep only likely text files from the non-php/css list.
+	 *
+	 * @param array $other_files Folder names, file paths and content for other files.
+	 * @return array
+	 */
+	protected function filter_other_text_files( $other_files ) {
+		$text_extensions = '/\.(txt|md|html|htm|json|js|xml|svg|po|pot|php|css)$/i';
+		$text_files      = array();
+
+		foreach ( $other_files as $file_path => $file_content ) {
+			if ( preg_match( $text_extensions, $file_path ) ) {
+				$text_files[ $file_path ] = $file_content;
+			}
+		}
+
+		return $text_files;
+	}
+
+	/**
+	 * Find non-compliant spellings of "WordPress" on a per-line basis.
+	 *
+	 * Detects:
+	 * - Incorrect capitalization variants such as "Wordpress" and plain "wordpress" in text.
+	 * - Common typos such as "word press" and "wordpres".
+	 *
+	 * @param string $content File content.
+	 * @return array Line number => line content for violating lines.
+	 */
+	protected function find_bad_spellings( $content ) {
+		$violation_lines    = array();
+		$normalized_content = $this->normalize_content_for_check( $content );
+		$normalized_lines   = preg_split( "/\r\n|\n|\r/", $normalized_content );
+		$original_lines     = preg_split( "/\r\n|\n|\r/", $content );
+
+		foreach ( $normalized_lines as $line_index => $line_content ) {
+			if ( preg_match( '/\bword\s+press\b/i', $line_content ) || preg_match( '/\bwordpres\b/i', $line_content ) ) {
+				$line_number                     = $line_index + 1;
+				$violation_lines[ $line_number ] = isset( $original_lines[ $line_index ] ) ? $original_lines[ $line_index ] : '';
+				continue;
+			}
+
+			if ( ! preg_match_all( '/\bwordpress\b/i', $line_content, $matches, PREG_OFFSET_CAPTURE ) ) {
+				continue;
+			}
+
+			foreach ( $matches[0] as $match ) {
+				$word   = $match[0];
+				$offset = $match[1];
+
+				if ( 'WordPress' === $word ) {
+					continue;
+				}
+
+				if ( 'wordpress' === $word && $this->is_allowed_lowercase_url_context( $line_content, $offset, strlen( $word ) ) ) {
+					continue;
+				}
+
+				$line_number                     = $line_index + 1;
+				$violation_lines[ $line_number ] = isset( $original_lines[ $line_index ] ) ? $original_lines[ $line_index ] : '';
+				break;
+			}
+		}
+
+		return $violation_lines;
+	}
+
+	/**
+	 * Build grep-like context only for actual violating matches.
+	 *
+	 * @param array $violation_lines Line number => line text for real violations.
+	 * @return string HTML snippet matching existing tc_grep-style output.
+	 */
+	protected function build_violation_context( $violation_lines ) {
+		$line_grep = '';
+
+		foreach ( $violation_lines as $line_number => $line_text ) {
+			$line_grep .= "<pre class='tc-grep'>" . __( 'Line ', 'theme-check' ) . $line_number . ': ' . htmlspecialchars( $line_text ) . '</pre>';
+		}
+
+		return $line_grep;
+	}
+
+	/**
+	 * Normalize file content before scanning for misspellings.
+	 *
+	 * This keeps line structure intact while masking known false-positive regions.
+	 *
+	 * @param string $content File content.
+	 * @return string
+	 */
+	protected function normalize_content_for_check( $content ) {
+		$content = $this->mask_block_comments( $content );
+		$content = $this->mask_wordpress_in_html_attributes( $content );
+
+		return $content;
+	}
+
+	/**
+	 * Mask Gutenberg block comments before checking text capitalization.
+	 *
+	 * Keep original length and line breaks so match offsets still map to real lines.
+	 *
+	 * @param string $content File content.
+	 * @return string
+	 */
+	protected function mask_block_comments( $content ) {
+		return preg_replace_callback(
+			'/<!--\s*\/?wp:[\s\S]*?-->/',
+			function ( $comment_match ) {
+				return preg_replace( '/[^\r\n]/', ' ', $comment_match[0] );
+			},
+			$content
+		);
+	}
+
+	/**
+	 * Mask any "wordpress" token inside HTML attribute values.
+	 *
+	 * Attribute values often contain slugs/service identifiers rather than user-facing text.
+	 *
+	 * @param string $content File content.
+	 * @return string
+	 */
+	protected function mask_wordpress_in_html_attributes( $content ) {
+		// Attribute values are machine data in many templates; skip spelling checks there.
+		return preg_replace_callback(
+			'/<[^>]+>/s',
+			function ( $tag_match ) {
+				return preg_replace_callback(
+					'/=\s*("[^"]*"|\'[^\']*\')/s',
+					function ( $attribute_match ) {
+						return preg_replace_callback(
+							'/\bwordpress\b/i',
+							function ( $word_match ) {
+								return str_repeat( 'x', strlen( $word_match[0] ) );
+							},
+							$attribute_match[0]
+						);
+					},
+					$tag_match[0]
+				);
+			},
+			$content
+		);
+	}
+
+	/**
+	 * Determine if lowercase "wordpress" appears in an allowed URL-like context.
+	 *
+	 * @param string $content The current line content.
+	 * @param int    $offset  Offset of the match in the line.
+	 * @param int    $length  Length of the match.
+	 * @return bool
+	 */
+	protected function is_allowed_lowercase_url_context( $content, $offset, $length ) {
+		$before = '';
+		$after  = '';
+
+		if ( $offset > 0 ) {
+			$before = $content[ $offset - 1 ];
+		}
+
+		if ( ( $offset + $length ) < strlen( $content ) ) {
+			$after = $content[ $offset + $length ];
+		}
+
+		$allowed_neighbors = array( '/', '.', '-', '_', ':', '?', '#', '&', '=', '%', '@' );
+
+		return in_array( $before, $allowed_neighbors, true ) || in_array( $after, $allowed_neighbors, true );
+	}
+}
+// phpcs:enable WordPress.WP.CapitalPDangit
+
+$themechecks[] = new WordPress_Spelling_Check();