diff --git a/.changeset/long-peas-repeat.md b/.changeset/long-peas-repeat.md
new file mode 100644
index 0000000000..1ea65056b4
--- /dev/null
+++ b/.changeset/long-peas-repeat.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-techdocs-node': patch
+---
+
+Add support for mapping custom tags in the techdocs yaml parser that validates the mkdocs.yaml file
diff --git a/plugins/techdocs-node/src/stages/generate/__fixtures__/mkdocs_with_extensions.yml b/plugins/techdocs-node/src/stages/generate/__fixtures__/mkdocs_with_extensions.yml
index d6c6858722..d1209d0c21 100644
--- a/plugins/techdocs-node/src/stages/generate/__fixtures__/mkdocs_with_extensions.yml
+++ b/plugins/techdocs-node/src/stages/generate/__fixtures__/mkdocs_with_extensions.yml
@@ -4,4 +4,9 @@ site_description: Test site description
 markdown_extensions:
   - pymdownx.emoji:
       emoji_index: !!python/name:materialx.emoji.twemoji
-      emoji_generator: !!python/name:materialx.emoji.to_svg
+      emoji_generator: !!python/object.apply:materialx.emoji.to_svg
+  - pymdownx.tabbed:
+      alternate_style: true
+      slugify: !!python/object/apply:pymdownx.slugs.slugify
+        kwds:
+          case: lower
diff --git a/plugins/techdocs-node/src/stages/generate/helpers.test.ts b/plugins/techdocs-node/src/stages/generate/helpers.test.ts
index 755cd9d1a6..af61dae936 100644
--- a/plugins/techdocs-node/src/stages/generate/helpers.test.ts
+++ b/plugins/techdocs-node/src/stages/generate/helpers.test.ts
@@ -247,6 +247,10 @@ describe('helpers', () => {
       expect(updatedMkdocsYml.toString()).toContain(
         "emoji_index: !!python/name:materialx.emoji.twemoji ''",
       );
+      expect(updatedMkdocsYml.toString()).toContain(
+        'slugify: !!python/object/apply:pymdownx.slugs.slugify',
+      );
+      expect(updatedMkdocsYml.toString()).toContain('case: lower');
     });
 
     it('should not override existing repo_url in mkdocs.yml', async () => {
diff --git a/plugins/techdocs-node/src/stages/generate/helpers.ts b/plugins/techdocs-node/src/stages/generate/helpers.ts
index d62b6dcccd..0cba56cfa5 100644
--- a/plugins/techdocs-node/src/stages/generate/helpers.ts
+++ b/plugins/techdocs-node/src/stages/generate/helpers.ts
@@ -141,6 +141,14 @@ export const MKDOCS_SCHEMA = DEFAULT_SCHEMA.extend([
     instanceOf: UnknownTag,
     construct: (data: string, type?: string) => new UnknownTag(data, type),
   }),
+  new Type('tag:', {
+    kind: 'mapping',
+    multi: true,
+    representName: o => (o as UnknownTag).type,
+    represent: o => (o as UnknownTag).data ?? '',
+    instanceOf: UnknownTag,
+    construct: (data: string, type?: string) => new UnknownTag(data, type),
+  }),
   new Type('', {
     kind: 'sequence',
     multi: true,