diff --git a/packages/effect-mongodb/src/Collection.ts b/packages/effect-mongodb/src/Collection.ts
index c0a5a49..df348f9 100644
--- a/packages/effect-mongodb/src/Collection.ts
+++ b/packages/effect-mongodb/src/Collection.ts
@@ -16,7 +16,10 @@ import type {
   FindOptions as MongoFindOptions,
   InsertManyResult,
   InsertOneOptions,
-  InsertOneResult
+  InsertOneResult,
+  UpdateFilter,
+  UpdateOptions,
+  UpdateResult
 } from "mongodb"
 import * as FindCursor from "./FindCursor.js"
 import type { Filter } from "./internal/filter.js"
@@ -175,4 +178,33 @@ export const deleteMany: {
     )
 )
 
+export const updateMany: {
+  <I extends Document>(
+    filter: Filter<I>,
+    update: UpdateFilter<I> | Array<Document>,
+    options?: UpdateOptions
+  ): <A extends Document, R>(
+    collection: Collection<A, I, R>
+  ) => Effect.Effect<UpdateResult, MongoError.MongoError, R>
+  <A extends Document, I extends Document, R>(
+    collection: Collection<A, I, R>,
+    filter: Filter<I>,
+    update: UpdateFilter<I> | Array<Document>,
+    options?: UpdateOptions
+  ): Effect.Effect<UpdateResult, MongoError.MongoError, R>
+} = F.dual(
+  (args) => isCollection(args[0]),
+  <A extends Document, I extends Document, R>(
+    collection: Collection<A, I, R>,
+    filter: Filter<I>,
+    update: UpdateFilter<I> | Array<Document>,
+    options?: UpdateOptions
+  ): Effect.Effect<UpdateResult, MongoError.MongoError, R> =>
+    Effect.promise(() =>
+      collection.collection.updateMany(filter, update as UpdateFilter<Document> | Array<Document>, options)
+    ).pipe(
+      Effect.catchAllDefect(MongoError.mongoErrorDie<UpdateResult>("updateMany error"))
+    )
+)
+
 const isCollection = (x: unknown) => x instanceof Collection
diff --git a/packages/effect-mongodb/src/DocumentCollection.ts b/packages/effect-mongodb/src/DocumentCollection.ts
index 3a45428..391954c 100644
--- a/packages/effect-mongodb/src/DocumentCollection.ts
+++ b/packages/effect-mongodb/src/DocumentCollection.ts
@@ -17,7 +17,10 @@ import type {
   InsertManyResult,
   InsertOneOptions,
   InsertOneResult,
-  OptionalUnlessRequiredId
+  OptionalUnlessRequiredId,
+  UpdateFilter,
+  UpdateOptions,
+  UpdateResult
 } from "mongodb"
 import * as Collection from "./Collection.js"
 import * as DocumentFindCursor from "./DocumentFindCursor.js"
@@ -164,6 +167,34 @@ export const deleteMany: {
     )
 )
 
+export const updateMany: {
+  (
+    filter: Filter<Document>,
+    update: UpdateFilter<Document> | Array<Document>,
+    options?: UpdateOptions
+  ): (
+    collection: DocumentCollection
+  ) => Effect.Effect<UpdateResult, MongoError.MongoError>
+  (
+    collection: DocumentCollection,
+    filter: Filter<Document>,
+    update: UpdateFilter<Document> | Array<Document>,
+    options?: UpdateOptions
+  ): Effect.Effect<UpdateResult, MongoError.MongoError>
+} = F.dual(
+  (args) => isDocumentCollection(args[0]),
+  (
+    collection: DocumentCollection,
+    filter: Filter<Document>,
+    update: UpdateFilter<Document> | Array<Document>,
+    options?: UpdateOptions
+  ): Effect.Effect<UpdateResult, MongoError.MongoError> =>
+    F.pipe(
+      Effect.promise(() => collection.collection.updateMany(filter, update, options)),
+      Effect.catchAllDefect(MongoError.mongoErrorDie<UpdateResult>("updateMany error"))
+    )
+)
+
 export const typed: {
   <A extends Document, I extends Document = A, R = never>(
     schema: Schema.Schema<A, I, R>