diff --git a/.gitignore b/.gitignore
index fe8741cf69..ca398154b7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,4 +16,5 @@ Gemfile.lock
 
 /container_gem_cache/
 /dist/
-/scripts/generate-related/data/
\ No newline at end of file
+/scripts/generate-related/data/
+/pa11y-ci-urls.js
diff --git a/generate_pa11y_ci_urls_from_git_diff.sh b/generate_pa11y_ci_urls_from_git_diff.sh
new file mode 100644
index 0000000000..cccff755bf
--- /dev/null
+++ b/generate_pa11y_ci_urls_from_git_diff.sh
@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+# Take in a base ref. Gets the files that have changed from the base to the HEAD.
+# Export the list as a CommonJS module for the pa11y-ci configuration to use.
+# Typical usage: generate_pa11y_ci_urls_from_git_diff.sh gh-pages > .pa11yci.js
+
+function generate_pa11y_ci_urls_from_git_diff {
+  base_ref=$1
+  if [ -z "$base_ref" ]; then
+    echo "No Git base ref provided. Usage: $0 <base_ref>"
+    exit 1
+  fi
+
+  changed_files=$(git diff --name-only $base_ref)
+
+  echo -n "module.exports=[";
+  for file in $changed_files; do
+    if [[ $file == _posts/* ]]; then
+      echo -n "'/$(url_of_post $file)',";
+    elif [[ $file == *.html && ! $file == _includes/* && ! $file == _layouts/* ]]; then
+      echo -n "'/$(url_of_page $file)',";
+    fi
+  done
+  echo -n "];";
+}
+
+function url_of_page {
+  echo $1 | sed "s/\(\/\?index\)\?\.html$//";
+}
+
+function url_of_post {
+  year="\([0-9][0-9][0-9][0-9]\)"
+  month="\([0-9][0-9]\)"
+  day="\([0-9][0-9]\)"
+  slug="\(.*\)"
+  file_ext="\(html\|markdown\|md\)"
+
+  echo $1 | sed "s/^_posts\/$year-$month-$day-$slug\.$file_ext$/\1\/\2\/\3\/\4.html/";
+}
+
+generate_pa11y_ci_urls_from_git_diff $1
+