diff --git a/apps/server/src/core/label/dto/label.dto.ts b/apps/server/src/core/label/dto/label.dto.ts
index e4ff7d4c..9b3540e0 100644
--- a/apps/server/src/core/label/dto/label.dto.ts
+++ b/apps/server/src/core/label/dto/label.dto.ts
@@ -6,8 +6,14 @@ import {
   IsOptional,
   IsString,
   IsUUID,
+  Matches,
   MaxLength,
 } from 'class-validator';
+import { Transform } from 'class-transformer';
+
+function normalizeLabel(name: string): string {
+  return name.trim().replace(/\s+/g, '-').toLowerCase();
+}
 
 export class AddLabelsDto {
   @IsString()
@@ -19,7 +25,14 @@ export class AddLabelsDto {
   @ArrayMaxSize(25)
   @IsString({ each: true })
   @IsNotEmpty({ each: true })
+  @Transform(({ value }) =>
+    Array.isArray(value) ? value.map(normalizeLabel) : value,
+  )
   @MaxLength(100, { each: true })
+  @Matches(/^[a-z0-9_~-]+$/, {
+    each: true,
+    message: 'Label names can only contain letters, numbers, hyphens, underscores, and tildes',
+  })
   names: string[];
 }
 
diff --git a/apps/server/src/database/migrations/20260217T120000-labels.ts b/apps/server/src/database/migrations/20260217T120000-labels.ts
index 4811baad..c3a258b8 100644
--- a/apps/server/src/database/migrations/20260217T120000-labels.ts
+++ b/apps/server/src/database/migrations/20260217T120000-labels.ts
@@ -19,9 +19,9 @@ export async function up(db: Kysely<any>): Promise<void> {
     .execute();
 
   await db.schema
-    .createIndex('labels_workspace_id_lower_name_unique')
+    .createIndex('labels_workspace_id_name_unique')
     .on('labels')
-    .expression(sql`workspace_id, LOWER(name)`)
+    .columns(['workspace_id', 'name'])
     .unique()
     .execute();
 
diff --git a/apps/server/src/database/repos/label/label.repo.ts b/apps/server/src/database/repos/label/label.repo.ts
index c5e75125..345b5bee 100644
--- a/apps/server/src/database/repos/label/label.repo.ts
+++ b/apps/server/src/database/repos/label/label.repo.ts
@@ -3,7 +3,6 @@ import { InjectKysely } from 'nestjs-kysely';
 import { KyselyDB, KyselyTransaction } from '../../types/kysely.types';
 import { Label } from '@docmost/db/types/entity.types';
 import { dbOrTx } from '@docmost/db/utils';
-import { sql } from 'kysely';
 import { SpaceMemberRepo } from '@docmost/db/repos/space/space-member.repo';
 
 @Injectable()
@@ -34,7 +33,7 @@ export class LabelRepo {
     return db
       .selectFrom('labels')
       .selectAll()
-      .where(sql`LOWER(name)`, '=', name.toLowerCase())
+      .where('name', '=', name.toLowerCase())
       .where('workspaceId', '=', workspaceId)
       .executeTakeFirst();
   }
@@ -45,15 +44,13 @@ export class LabelRepo {
     trx?: KyselyTransaction,
   ): Promise<Label> {
     const db = dbOrTx(this.db, trx);
-    const trimmedName = name.trim();
+    const normalizedName = name.trim().toLowerCase();
 
     const result = await db
       .insertInto('labels')
-      .values({ name: trimmedName, workspaceId })
+      .values({ name: normalizedName, workspaceId })
       .onConflict((oc) =>
-        oc
-          .expression(sql`workspace_id, LOWER(name)`)
-          .doNothing(),
+        oc.columns(['name', 'workspaceId']).doNothing(),
       )
       .returningAll()
       .executeTakeFirst();
@@ -62,7 +59,7 @@ export class LabelRepo {
       return result;
     }
 
-    return this.findByNameAndWorkspace(trimmedName, workspaceId, trx);
+    return this.findByNameAndWorkspace(normalizedName, workspaceId, trx);
   }
 
   async findLabelsByPageId(pageId: string): Promise<Label[]> {