Accessibility SEO
Accessibility SEO is the practice of making pages usable for people with disabilities so search engines can better understand, crawl, and index the content.
What I’d do first
- Run an automated scan to find missing alt text, empty headings, and low contrast.
- Fix heading hierarchy and semantic HTML before touching anything else.
- Add descriptive alt text to images — describe the image, don't stuff keywords.
- Test keyboard navigation: can you tab through every interactive element?
- Use a screen reader to test your core user journeys — you'll catch things no tool can.
Here's what I'd do first if I were starting from scratch.
The path I'd take
- Audit your current state — Use Lighthouse or WAVE to get a baseline. Note every missing alt text, empty heading, and low-contrast area.
- Fix semantic structure first — Convert div-heavy layouts to proper HTML5 landmarks (
<nav>,<main>,<aside>). Add a logical heading hierarchy. - Add text alternatives to all media — Every image gets descriptive alt text. Every video gets captions (even auto-captions are better than nothing). Every audio file gets a transcript.
- Ensure keyboard access — Make sure all interactive elements are reachable and operable via keyboard. Add visible focus indicators (don't just remove
outline: nonewithout a replacement). - Check color contrast — Use a tool like WebAIM Contrast Checker. Aim for at least 4.5:1 for normal text, 3:1 for large text.
- Test with real assistive tech — Turn on a screen reader (VoiceOver on Mac, NVDA on Windows) and try to complete your core user journeys. You'll catch things no automated tool can.
Watch-outs
- Don't keyword-stuff alt text — "red running shoes for marathon training buy now" is bad for accessibility and bad for SEO. Write "Red running shoes on a track" instead.
- Don't rely on color alone — If you use red to indicate required fields, also add an asterisk or text label. Colorblind users and search engines both miss color-only cues.
- Don't hide content behind JavaScript that doesn't degrade gracefully — If a screen reader or Googlebot can't reach your content, it doesn't exist.
- Don't skip skip links — A "Skip to main content" link at the top of the page is a tiny addition that dramatically improves keyboard navigation.
What I got wrong
I used to think accessibility was just about alt text and contrast. I ignored things like form labels, error messages, and focus management. Turns out, a form with unlabeled fields is a form that neither a screen reader user nor Googlebot can fill out reliably. I also assumed automated tools caught everything — they don't. A tool can tell you an image has alt text, but it can't tell you if that alt text is actually useful. The real learning was: accessibility SEO is about intent, not just compliance.
Next step
Quick answers
Does accessibility directly affect rankings?
Google has said accessibility is not a direct ranking factor, but many accessibility best practices overlap with signals that do matter — like page experience, mobile usability, and content clarity.
What's the easiest accessibility fix for SEO?
Adding descriptive alt text to images. It helps screen readers and gives search engines more context for image search.
Can I use an accessibility overlay plugin?
Overlays are generally not recommended by the accessibility community. They often fail to fix underlying code issues and can introduce new problems for assistive tech users.
Sources
Primary documentation is linked directly. Anything commercial is marked nofollow.
- Google Search Central — Best primary source for how Google crawls, renders, and evaluates page content and usability signals.
- W3C WCAG — Primary accessibility standard for contrast, keyboard access, text alternatives, and structure.
- Moz — Well-known SEO reference with practical guidance on the overlap between technical SEO and accessibility.
- Deque — Respected accessibility vendor with detailed overlap examples relevant to SEO teams.
- Siteimprove — Useful practitioner guide covering shared SEO and accessibility tactics such as navigation, semantics, contrast, and media text alternatives.
Notes from Callum Bennett.