diff --git a/src/datasources/product-api.ts b/src/datasources/product-api.ts
index 07b1afb..a15c809 100644
--- a/src/datasources/product-api.ts
+++ b/src/datasources/product-api.ts
@@ -621,4 +621,32 @@ export class ProductAPI extends BaseSQLDataSource {
     promises.push(query);
     return Promise.all(promises);
   }
+
+  async addCategoriesToProduct(
+    productId,
+    categoryIds,
+  ): Promise<Promise<void>[]> {
+    const promises = categoryIds.map((categoryId) =>
+      this.knex('product_category').insert({
+        product_id: productId,
+        category_id: categoryId,
+      }),
+    );
+    return Promise.all(promises);
+  }
+
+  async removeCategoriesFromProduct(
+    productId,
+    categoryIds,
+  ): Promise<Promise<void>[]> {
+    const promises = categoryIds.map((categoryId) =>
+      this.knex('product_category')
+        .where({
+          product_id: productId,
+          category_id: categoryId,
+        })
+        .del(),
+    );
+    return Promise.all(promises);
+  }
 }
diff --git a/src/resolvers/products-resolver.ts b/src/resolvers/products-resolver.ts
index d9935f2..f7b5416 100644
--- a/src/resolvers/products-resolver.ts
+++ b/src/resolvers/products-resolver.ts
@@ -222,4 +222,24 @@ export const productMutationTypeDefs = {
     );
     return (<ProductAPI>dataSources.productApi).getProduct(productId);
   },
+
+  async addCategoriesToProduct(_, { productId, categoryIds }, { dataSources }) {
+    await (<ProductAPI>dataSources.productApi).addCategoriesToProduct(
+      productId,
+      categoryIds,
+    );
+    return (<ProductAPI>dataSources.productApi).getProduct(productId);
+  },
+
+  async removeCategoriesFromProduct(
+    _,
+    { productId, categoryIds },
+    { dataSources },
+  ) {
+    await (<ProductAPI>dataSources.productApi).removeCategoriesFromProduct(
+      productId,
+      categoryIds,
+    );
+    return (<ProductAPI>dataSources.productApi).getProduct(productId);
+  },
 };
diff --git a/src/schema.graphql b/src/schema.graphql
index 7bd2b0c..0c91627 100644
--- a/src/schema.graphql
+++ b/src/schema.graphql
@@ -466,4 +466,7 @@ type Mutation {
   removeRelatedProducts(productId: Int!, relatedProductIds: [Int]!): Product
 
   addKeyword(name: String!, type: KeywordType): Keyword
+
+  addCategoriesToProduct(productId: Int!, categoryIds: [Int]!): Product
+  removeCategoriesFromProduct(productId: Int!, categoryIds: [Int]!): Product
 }