diff --git a/google-cloud-error_reporting/lib/google/cloud/error_reporting.rb b/google-cloud-error_reporting/lib/google/cloud/error_reporting.rb
index 28aa231c4ef4..7858b0f2741d 100644
--- a/google-cloud-error_reporting/lib/google/cloud/error_reporting.rb
+++ b/google-cloud-error_reporting/lib/google/cloud/error_reporting.rb
@@ -88,12 +88,15 @@ def self.new project_id: nil,
         scope         ||= configure.scope
         timeout       ||= configure.timeout
         endpoint      ||= configure.endpoint
+        quota_project   = configure.quota_project
         credentials   ||= keyfile || default_credentials(scope: scope)
 
         credentials = resolve_credentials credentials, scope
         project_id = resolve_project_id project_id, credentials
 
-        service = ErrorReporting::Service.new project_id, credentials, host: endpoint, timeout: timeout
+        service = ErrorReporting::Service.new project_id, credentials,
+                                              host: endpoint, timeout: timeout,
+                                              quota_project: quota_project
         ErrorReporting::Project.new service
       end
 
diff --git a/google-cloud-error_reporting/lib/google/cloud/error_reporting/project.rb b/google-cloud-error_reporting/lib/google/cloud/error_reporting/project.rb
index cf65e373c50d..551328404eb8 100644
--- a/google-cloud-error_reporting/lib/google/cloud/error_reporting/project.rb
+++ b/google-cloud-error_reporting/lib/google/cloud/error_reporting/project.rb
@@ -122,8 +122,8 @@ def project_id
         #   error_event = error_reporting.error_event "Error with Backtrace"
         #   error_reporting.report error_event
         #
-        def report *args, &block
-          service.report(*args, &block)
+        def report(*args, &)
+          service.report(*args, &)
         end
 
         ##
diff --git a/google-cloud-error_reporting/lib/google/cloud/error_reporting/service.rb b/google-cloud-error_reporting/lib/google/cloud/error_reporting/service.rb
index ef43277e5aa8..8736b3b071ef 100644
--- a/google-cloud-error_reporting/lib/google/cloud/error_reporting/service.rb
+++ b/google-cloud-error_reporting/lib/google/cloud/error_reporting/service.rb
@@ -29,14 +29,16 @@ class Service
         attr_accessor :credentials
         attr_accessor :timeout
         attr_accessor :host
+        attr_accessor :quota_project
 
         ##
         # Creates a new Service instance.
-        def initialize project, credentials, timeout: nil, host: nil
+        def initialize project, credentials, timeout: nil, host: nil, quota_project: nil
           @project = project
           @credentials = credentials
           @timeout = timeout
           @host = host
+          @quota_project = quota_project || (credentials.quota_project_id if credentials.respond_to? :quota_project_id)
         end
 
         def error_reporting
@@ -46,6 +48,7 @@ def error_reporting
               config.credentials = credentials if credentials
               config.timeout = timeout if timeout
               config.endpoint = host if host
+              config.quota_project = quota_project if quota_project
               config.lib_name = "gccl"
               config.lib_version = Google::Cloud::ErrorReporting::VERSION
             end
diff --git a/google-cloud-error_reporting/support/doctest_helper.rb b/google-cloud-error_reporting/support/doctest_helper.rb
index b179fbd0de4b..1af5f8409cd7 100644
--- a/google-cloud-error_reporting/support/doctest_helper.rb
+++ b/google-cloud-error_reporting/support/doctest_helper.rb
@@ -13,6 +13,7 @@
 # limitations under the License.
 
 require "minitest/focus"
+require "ostruct"
 
 require "google/cloud/error_reporting"
 
@@ -73,13 +74,13 @@ def mock_error_reporting
 
   doctest.before "Google::Cloud#error_reporting" do
     mock_error_reporting do |mock|
-      mock.expect :report_error_event, nil, [Hash]
+      mock.expect :report_error_event, nil, [], project_name: Object, event: Object
     end
   end
 
   doctest.before "Google::Cloud.error_reporting" do
     mock_error_reporting do |mock|
-      mock.expect :report_error_event, nil, [Hash]
+      mock.expect :report_error_event, nil, [], project_name: Object, event: Object
     end
   end
 
@@ -89,13 +90,13 @@ def mock_error_reporting
 
   doctest.before "Google::Cloud::ErrorReporting::ErrorEvent" do
     mock_error_reporting do |mock|
-      mock.expect :report_error_event, nil, [Hash]
+      mock.expect :report_error_event, nil, [], project_name: Object, event: Object
     end
   end
 
   doctest.before "Google::Cloud::ErrorReporting::Project" do
     mock_error_reporting do |mock|
-      mock.expect :report_error_event, nil, [Hash]
+      mock.expect :report_error_event, nil, [], project_name: Object, event: Object
     end
   end
 
@@ -103,7 +104,7 @@ def mock_error_reporting
 
   doctest.before "Google::Cloud::ErrorReporting::Service" do
     mock_error_reporting do |mock|
-      mock.expect :report_error_event, nil, [Hash]
+      mock.expect :report_error_event, nil, [], project_name: Object, event: Object
     end
   end
 end
diff --git a/google-cloud-error_reporting/test/google/cloud/error_reporting/service_test.rb b/google-cloud-error_reporting/test/google/cloud/error_reporting/service_test.rb
new file mode 100644
index 000000000000..c4e0996e00fd
--- /dev/null
+++ b/google-cloud-error_reporting/test/google/cloud/error_reporting/service_test.rb
@@ -0,0 +1,66 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+require "helper"
+require "signet/oauth_2/client"
+
+describe Google::Cloud::ErrorReporting::Service do
+  let(:project) { "test-project" }
+  let(:credentials) do
+    creds = Signet::OAuth2::Client.new
+    def creds.quota_project_id
+      "credentials-quota-project"
+    end
+    def creds.disable_universe_domain_check
+      true
+    end
+    creds
+  end
+
+  describe ".new" do
+    it "sets project and credentials" do
+      service = Google::Cloud::ErrorReporting::Service.new project, credentials
+      _(service.project).must_equal project
+      _(service.credentials).must_equal credentials
+    end
+
+    it "accepts quota_project" do
+      quota_project = "test-quota-project"
+      service = Google::Cloud::ErrorReporting::Service.new project, credentials, quota_project: quota_project
+      _(service.quota_project).must_equal quota_project
+    end
+
+    it "falls back to credentials quota_project_id if not explicitly passed" do
+      service = Google::Cloud::ErrorReporting::Service.new project, credentials
+      _(service.quota_project).must_equal "credentials-quota-project"
+    end
+  end
+
+  describe "#error_reporting" do
+    it "configures the gRPC client with quota_project" do
+      quota_project = "test-quota-project"
+      service = Google::Cloud::ErrorReporting::Service.new project, credentials, quota_project: quota_project
+      
+      client = service.error_reporting
+      _(client.configure.quota_project).must_equal quota_project
+    end
+
+    it "configures the gRPC client with credentials quota_project" do
+      service = Google::Cloud::ErrorReporting::Service.new project, credentials
+      
+      client = service.error_reporting
+      _(client.configure.quota_project).must_equal "credentials-quota-project"
+    end
+  end
+end
diff --git a/google-cloud-error_reporting/test/google/cloud/error_reporting_test.rb b/google-cloud-error_reporting/test/google/cloud/error_reporting_test.rb
index f01c3c01eb56..42308a175500 100644
--- a/google-cloud-error_reporting/test/google/cloud/error_reporting_test.rb
+++ b/google-cloud-error_reporting/test/google/cloud/error_reporting_test.rb
@@ -66,7 +66,7 @@ def creds.is_a? target
 
     it "uses provided endpoint" do
       endpoint = "errorreporting-endpoint2.example.com"
-      stubbed_service = ->(project, credentials, timeout: nil, host: nil) {
+      stubbed_service = ->(project, credentials, timeout: nil, host: nil, quota_project: nil) {
         _(project).must_equal "project-id"
         _(credentials).must_equal default_credentials
         _(timeout).must_be :nil?
@@ -85,6 +85,28 @@ def creds.is_a? target
       end
     end
 
+    it "uses configuration quota_project" do
+      quota_project = "configure-quota-project"
+      Google::Cloud::ErrorReporting.configure do |config|
+        config.quota_project = quota_project
+      end
+
+      stubbed_service = ->(project, credentials, timeout: nil, host: nil, quota_project: nil) {
+        _(project).must_equal "project-id"
+        _(quota_project).must_equal "configure-quota-project"
+        OpenStruct.new project: project
+      }
+
+      ENV.stub :[], nil do
+        Google::Cloud::ErrorReporting::Service.stub :new, stubbed_service do
+          error_reporting = Google::Cloud::ErrorReporting.new project_id: "project-id",
+                                                              credentials: default_credentials
+          _(error_reporting).must_be_kind_of Google::Cloud::ErrorReporting::Project
+        end
+      end
+      Google::Cloud::ErrorReporting.configure.reset!
+    end
+
     it "uses provided project (alias), keyfile (alias), service, and version" do
       stubbed_credentials = ->(keyfile, scope: nil) {
         _(keyfile).must_equal "/path/to/a/keyfile"
@@ -315,7 +337,7 @@ def creds.is_a? target
         _(scope).must_equal default_scopes
         "error_reporting-credentials"
       }
-      stubbed_service = ->(project, credentials, timeout: nil, host: nil) {
+      stubbed_service = ->(project, credentials, timeout: nil, host: nil, quota_project: nil) {
         _(project).must_equal "project-id"
         _(credentials).must_equal "error_reporting-credentials"
         _(timeout).must_be :nil?
@@ -352,7 +374,7 @@ def creds.is_a? target
         _(scope).must_equal default_scopes
         "error_reporting-credentials"
       }
-      stubbed_service = ->(project, credentials, timeout: nil, host: nil) {
+      stubbed_service = ->(project, credentials, timeout: nil, host: nil, quota_project: nil) {
         _(project).must_equal "project-id"
         _(credentials).must_equal "error_reporting-credentials"
         _(timeout).must_be :nil?
@@ -389,7 +411,7 @@ def creds.is_a? target
         _(scope).must_equal default_scopes
         "error_reporting-credentials"
       }
-      stubbed_service = ->(project, credentials, timeout: nil, host: nil) {
+      stubbed_service = ->(project, credentials, timeout: nil, host: nil, quota_project: nil) {
         _(project).must_equal "project-id"
         _(credentials).must_equal "error_reporting-credentials"
         _(timeout).must_equal 42
@@ -423,7 +445,7 @@ def creds.is_a? target
 
     it "uses error_reporting config for endpoint" do
       endpoint = "errorreporting-endpoint2.example.com"
-      stubbed_service = ->(project, credentials, timeout: nil, host: nil) {
+      stubbed_service = ->(project, credentials, timeout: nil, host: nil, quota_project: nil) {
         _(project).must_equal "project-id"
         _(credentials).must_equal default_credentials
         _(timeout).must_be :nil?
@@ -454,7 +476,7 @@ def creds.is_a? target
         _(scope).must_equal default_scopes
         "error_reporting-credentials"
       }
-      stubbed_service = ->(project, credentials, timeout: nil, host: nil) {
+      stubbed_service = ->(project, credentials, timeout: nil, host: nil, quota_project: nil) {
         _(project).must_equal "project-id"
         _(credentials).must_equal "error_reporting-credentials"
         _(timeout).must_equal 42