diff --git a/ghost/core/test/e2e-api/admin/__snapshots__/mentions.test.js.snap b/ghost/core/test/e2e-api/admin/__snapshots__/mentions.test.js.snap
index d7be69a6e5..afa69aebcf 100644
--- a/ghost/core/test/e2e-api/admin/__snapshots__/mentions.test.js.snap
+++ b/ghost/core/test/e2e-api/admin/__snapshots__/mentions.test.js.snap
@@ -12,7 +12,7 @@ Object {
       "source_excerpt": null,
       "source_favicon": null,
       "source_featured_image": null,
-      "source_site_title": null,
+      "source_site_title": "source.com",
       "source_title": Any<String>,
       "target": Any<String>,
       "timestamp": StringMatching /\\\\d\\{4\\}-\\\\d\\{2\\}-\\\\d\\{2\\}T\\\\d\\{2\\}:\\\\d\\{2\\}:\\\\d\\{2\\}\\\\\\.000Z/,
@@ -27,7 +27,7 @@ Object {
       "source_excerpt": null,
       "source_favicon": null,
       "source_featured_image": null,
-      "source_site_title": null,
+      "source_site_title": "anothersource.com",
       "source_title": Any<String>,
       "target": Any<String>,
       "timestamp": StringMatching /\\\\d\\{4\\}-\\\\d\\{2\\}-\\\\d\\{2\\}T\\\\d\\{2\\}:\\\\d\\{2\\}:\\\\d\\{2\\}\\\\\\.000Z/,
diff --git a/ghost/webmentions/lib/Mention.js b/ghost/webmentions/lib/Mention.js
index 26e5cd031c..8ab6a8ff5a 100644
--- a/ghost/webmentions/lib/Mention.js
+++ b/ghost/webmentions/lib/Mention.js
@@ -112,7 +112,11 @@ module.exports = class Mention {
         /** @type {string | null} */
         const sourceExcerpt = validateString(metadata.sourceExcerpt, 2000, 'sourceExcerpt');
         /** @type {string | null} */
-        const sourceSiteTitle = validateString(metadata.sourceSiteTitle, 2000, 'sourceSiteTitle');
+        let sourceSiteTitle = validateString(metadata.sourceSiteTitle, 2000, 'sourceSiteTitle');
+        if (sourceSiteTitle === null) {
+            sourceSiteTitle = this.#source.host;
+        }
+
         /** @type {string | null} */
         const sourceAuthor = validateString(metadata.sourceAuthor, 2000, 'sourceAuthor');