Accessibility SEO
Improves page usability for people with disabilities, which also helps search engines better crawl, understand, and index your content.
If you treat accessibility as a quick SEO win and stuff alt text with keywords, you will harm both users and your rankings.
Key points
- Use semantic HTML like headings and landmarks to help both screen readers and search engines.
- Write descriptive alt text that explains the image, not keyword-stuffed descriptions.
- Ensure keyboard navigability for all interactive elements; it is a core accessibility requirement.
- Provide captions and transcripts for media to add indexable text and improve accessibility.
One site, two fixes, very different outcomes
A travel blog added alt text to all images but used generic keywords like 'beach holidays'. A competitor wrote descriptive alt text such as 'sunset over Santorini caldera with white-washed buildings'. The competitor's images appeared in Google Images for related searches, and their page later ranked for 'Santorini sunset'. The blog saw no improvement and had to redo its alt text.
Three ways accessibility fixes improve crawlability
- Semantic HTML structure Using proper headings, lists, and landmarks helps search engines parse page hierarchy and content relationships, which is also essential for screen readers. This mirrors the benefits of semantic markup.
- Descriptive alt text Alt text that accurately describes an image provides context for search engines and assists users with visual impairments. This is a foundational practice in image SEO.
- Keyboard navigability Ensuring all interactive elements are reachable and operable by keyboard improves user experience and helps search engines follow links and submit forms. Also benefits from seo amp compliance if using AMP.
Four common mistakes that hurt both users and search engines
- Keyword-stuffed alt text Writing alt text filled with keywords rather than descriptive content misleads search engines and ruins the experience for screen reader users. Always write for understanding first.
- Non-semantic div layouts Heavy use of divs without semantic headings or landmarks hides the content structure from assistive technologies and makes it harder for search engines to extract meaning.
- Poor colour contrast Using low-contrast text or relying solely on colour to convey information fails WCAG guidelines and makes content hard to read for everyone, including search engine crawlers.
- Missing media alternatives Publishing videos or audio without captions, transcripts, or accessible controls excludes users and misses the chance to add indexable text for search engines.
Three things to check before you start
- Current page structure Audit your headings, landmarks, and form labels to ensure they are semantic and correctly nested. This groundwork supports both accessibility and technical SEO.
- Colour contrast ratios Check that text and background colours meet WCAG AA standards for normal and large text. Use a contrast checker tool to verify compliance.
- Media accessibility Ensure all video and audio content has captions, transcripts, and usable controls. This also adds crawlable text and improves the multimedia experience.
Common questions
What is SEO?
SEO stands for Search Engine Optimisation, the practice of improving a site's visibility in search engines. Accessibility SEO applies these principles to make content usable for all users, including those with disabilities.
How does accessibility SEO work?
By applying semantic HTML, descriptive alt text, keyboard navigation, and media transcripts, you create a page that both users and search engines can easily parse.
Sources
- Google Search Central Official Google documentation on search and SEO best practices.
- W3C WCAG Web Content Accessibility Guidelines standards and techniques.
- Deque Article on seven tactics that benefit both accessibility and SEO.