diff --git a/packages/gatsby-plugin-google-analytics/README.md b/packages/gatsby-plugin-google-analytics/README.md
index a05b593df5f19..528c921818ec5 100644
--- a/packages/gatsby-plugin-google-analytics/README.md
+++ b/packages/gatsby-plugin-google-analytics/README.md
@@ -138,6 +138,7 @@ This plugin supports all optional Create Only Fields documented in [Google Analy
 - `alwaysSendReferrer`: boolean
 - `allowAnchor`: boolean
 - `cookieName`: string
+- `cookieFlags`: string
 - `cookieDomain`: string, defaults to `'auto'` if not given
 - `cookieExpires`: number
 - `storeGac`: boolean
diff --git a/packages/gatsby-plugin-google-analytics/src/gatsby-ssr.js b/packages/gatsby-plugin-google-analytics/src/gatsby-ssr.js
index 1644c904d2276..1afa395dc63b6 100644
--- a/packages/gatsby-plugin-google-analytics/src/gatsby-ssr.js
+++ b/packages/gatsby-plugin-google-analytics/src/gatsby-ssr.js
@@ -8,6 +8,7 @@ const knownOptions = {
     alwaysSendReferrer: `boolean`,
     allowAnchor: `boolean`,
     cookieName: `string`,
+    cookieFlags: `string`,
     cookieExpires: `number`,
     storeGac: `boolean`,
     legacyCookieDomain: `string`,