diff --git a/_config.yml b/_config.yml
index ba2b50db9660..a4d6de58a852 100644
--- a/_config.yml
+++ b/_config.yml
@@ -85,6 +85,7 @@ facebook:
   app_id                 :
   publisher              :
 og_image                 : # Open Graph/Twitter default site image
+og_image_alt             : # Alternative text for Open Graph/Twitter image for screen readers
 # For specifying social profiles
 # - https://developers.google.com/structured-data/customize/social-profiles
 social:
diff --git a/_includes/seo.html b/_includes/seo.html
index c9d01e946a60..122192141387 100644
--- a/_includes/seo.html
+++ b/_includes/seo.html
@@ -41,6 +41,9 @@
 {%- assign site_og_image = site.og_image | absolute_url -%}
 {%- assign site_og_image = site_og_image | escape -%}
 
+{%- assign site_og_image_alt = site.og_image_alt -%}
+{%- assign site_og_image_alt = site_og_image_alt | escape -%}
+
 {%- if page.date -%}
   {%- assign og_type = "article" -%}
 {%- else -%}
@@ -71,6 +74,7 @@
   <meta property="og:image" content="{{ page_large_image }}">
 {% elsif page_teaser_image %}
   <meta property="og:image" content="{{ page_teaser_image }}">
+  <meta property="og:image:alt" content="{{ site_og_image_alt }}">
 {% endif %}
 
 {% if site.twitter.username %}
@@ -86,6 +90,7 @@
     <meta name="twitter:card" content="summary">
     {% if page_teaser_image %}
       <meta name="twitter:image" content="{{ page_teaser_image }}">
+      <meta property="twitter:image:alt" content="{{ site_og_image_alt }}">
     {% endif %}
   {% endif %}
 
diff --git a/docs/_config.yml b/docs/_config.yml
index 6cba47ff893c..caa51003b377 100644
--- a/docs/_config.yml
+++ b/docs/_config.yml
@@ -78,6 +78,7 @@ facebook:
   app_id                 :
   publisher              :
 og_image                 : "/assets/images/site-logo.png" # Open Graph/Twitter default site image
+og_image_alt             : "Minimal mistakes logo" # Alternative text for screen readers
 # For specifying social profiles, used in _includes/seo.html
 # - https://developers.google.com/structured-data/customize/social-profiles
 social: