diff --git a/common/fold.ts b/common/fold.ts
index 3c6be6ab..e732e34d 100644
--- a/common/fold.ts
+++ b/common/fold.ts
@@ -7,6 +7,7 @@ export type Fold = {
   createdTime: number
 
   tags: string[]
+  lowercaseTags: string[]
 
   contractIds: string[]
   excludedContractIds: string[]
diff --git a/functions/src/create-fold.ts b/functions/src/create-fold.ts
index e86db2a1..36d1d269 100644
--- a/functions/src/create-fold.ts
+++ b/functions/src/create-fold.ts
@@ -59,6 +59,7 @@ export const createFold = functions.runWith({ minInstances: 1 }).https.onCall(
       name,
       about,
       tags,
+      lowercaseTags: tags.map((tag) => tag.toLowerCase()),
       createdTime: Date.now(),
       contractIds: [],
       excludedContractIds: [],
diff --git a/functions/src/scripts/lowercase-fold-tags.ts b/functions/src/scripts/lowercase-fold-tags.ts
new file mode 100644
index 00000000..bf7335ee
--- /dev/null
+++ b/functions/src/scripts/lowercase-fold-tags.ts
@@ -0,0 +1,34 @@
+import * as admin from 'firebase-admin'
+import * as _ from 'lodash'
+
+import { initAdmin } from './script-init'
+initAdmin('james')
+
+import { getValues } from '../utils'
+import { Fold } from '../../../common/fold'
+
+async function lowercaseFoldTags() {
+  const firestore = admin.firestore()
+  console.log('Updating fold tags')
+
+  const folds = await getValues<Fold>(firestore.collection('folds'))
+
+  console.log('Loaded', folds.length, 'folds')
+
+  for (const fold of folds) {
+    const foldRef = firestore.doc(`folds/${fold.id}`)
+
+    const { tags } = fold
+    const lowercaseTags = _.uniq(tags.map((tag) => tag.toLowerCase()))
+
+    console.log('Adding lowercase tags', fold.slug, lowercaseTags)
+
+    await foldRef.update({
+      lowercaseTags,
+    } as Partial<Fold>)
+  }
+}
+
+if (require.main === module) {
+  lowercaseFoldTags().then(() => process.exit())
+}
diff --git a/web/lib/firebase/folds.ts b/web/lib/firebase/folds.ts
index 2d3bef42..ef7090b1 100644
--- a/web/lib/firebase/folds.ts
+++ b/web/lib/firebase/folds.ts
@@ -135,9 +135,12 @@ export function listenForFollow(
 export function getFoldsByTags(tags: string[]) {
   if (tags.length === 0) return []
 
-  const lowercaseTags = tags.map((tag) => tag)
+  const lowercaseTags = tags.map((tag) => tag.toLowerCase())
   return getValues<Fold>(
     // TODO: split into multiple queries if tags.length > 10.
-    query(foldCollection, where('tags', 'array-contains-any', lowercaseTags))
+    query(
+      foldCollection,
+      where('lowercaseTags', 'array-contains-any', lowercaseTags)
+    )
   )
 }