diff --git a/app/models/project_services/kubernetes_service.rb b/app/models/project_services/kubernetes_service.rb
index b2494a0be6e..8977a7cdafe 100644
--- a/app/models/project_services/kubernetes_service.rb
+++ b/app/models/project_services/kubernetes_service.rb
@@ -77,6 +77,14 @@ class KubernetesService < DeploymentService
     ]
   end
 
+  def actual_namespace
+    if namespace.present?
+      namespace
+    else
+      default_namespace
+    end
+  end
+
   # Check we can connect to the Kubernetes API
   def test(*args)
     kubeclient = build_kubeclient!
@@ -91,7 +99,7 @@ class KubernetesService < DeploymentService
     variables = [
       { key: 'KUBE_URL', value: api_url, public: true },
       { key: 'KUBE_TOKEN', value: token, public: false },
-      { key: 'KUBE_NAMESPACE', value: namespace_variable, public: true }
+      { key: 'KUBE_NAMESPACE', value: actual_namespace, public: true }
     ]
 
     if ca_pem.present?
@@ -110,7 +118,7 @@ class KubernetesService < DeploymentService
     with_reactive_cache do |data|
       pods = data.fetch(:pods, nil)
       filter_pods(pods, app: environment.slug).
-        flat_map { |pod| terminals_for_pod(api_url, namespace, pod) }.
+        flat_map { |pod| terminals_for_pod(api_url, actual_namespace, pod) }.
         each { |terminal| add_terminal_auth(terminal, terminal_auth) }
     end
   end
@@ -124,7 +132,7 @@ class KubernetesService < DeploymentService
 
     # Store as hashes, rather than as third-party types
     pods = begin
-      kubeclient.get_pods(namespace: namespace).as_json
+      kubeclient.get_pods(namespace: actual_namespace).as_json
     rescue KubeException => err
       raise err unless err.error_code == 404
       []
@@ -142,20 +150,12 @@ class KubernetesService < DeploymentService
     default_namespace || TEMPLATE_PLACEHOLDER
   end
 
-  def namespace_variable
-    if namespace.present?
-      namespace
-    else
-      default_namespace
-    end
-  end
-
   def default_namespace
     "#{project.path}-#{project.id}" if project.present?
   end
 
   def build_kubeclient!(api_path: 'api', api_version: 'v1')
-    raise "Incomplete settings" unless api_url && namespace && token
+    raise "Incomplete settings" unless api_url && actual_namespace && token
 
     ::Kubeclient::Client.new(
       join_api_url(api_path),
diff --git a/changelogs/unreleased/fix-terminals-support-for-kubernetes-service.yml b/changelogs/unreleased/fix-terminals-support-for-kubernetes-service.yml
new file mode 100644
index 00000000000..fb91da9510c
--- /dev/null
+++ b/changelogs/unreleased/fix-terminals-support-for-kubernetes-service.yml
@@ -0,0 +1,4 @@
+---
+title: Fix terminals support for Kubernetes Service
+merge_request:
+author:
diff --git a/spec/factories/services.rb b/spec/factories/services.rb
index 28ddd0da753..3fad4d2d658 100644
--- a/spec/factories/services.rb
+++ b/spec/factories/services.rb
@@ -20,7 +20,6 @@ FactoryGirl.define do
     project factory: :empty_project
     active true
     properties({
-      namespace: 'somepath',
       api_url: 'https://kubernetes.example.com',
       token: 'a' * 40
     })
diff --git a/spec/models/project_services/kubernetes_service_spec.rb b/spec/models/project_services/kubernetes_service_spec.rb
index c1c2f2a7219..57c51ebea7b 100644
--- a/spec/models/project_services/kubernetes_service_spec.rb
+++ b/spec/models/project_services/kubernetes_service_spec.rb
@@ -13,7 +13,7 @@ describe KubernetesService, models: true, caching: true do
   let(:discovery_url) { service.api_url + '/api/v1' }
   let(:discovery_response) { { body: kube_discovery_body.to_json } }
 
-  let(:pods_url) { service.api_url + "/api/v1/namespaces/#{service.namespace}/pods" }
+  let(:pods_url) { service.api_url + "/api/v1/namespaces/#{service.actual_namespace}/pods" }
   let(:pods_response) { { body: kube_pods_body(kube_pod).to_json } }
 
   def stub_kubeclient_discover
@@ -105,6 +105,34 @@ describe KubernetesService, models: true, caching: true do
     end
   end
 
+  describe '#actual_namespace' do
+    subject { service.actual_namespace }
+
+    it "returns the default namespace" do
+      is_expected.to eq(service.send(:default_namespace))
+    end
+    
+    context 'when namespace is specified' do
+      before do
+        service.namespace = 'my-namespace'
+      end
+
+      it "returns the user-namespace" do
+        is_expected.to eq('my-namespace')
+      end
+    end
+
+    context 'when service is not assigned to project' do
+      before do
+        service.project = nil
+      end
+
+      it "does not return namespace" do
+        is_expected.to be_nil
+      end
+    end
+  end
+
   describe '#test' do
     before do
       stub_kubeclient_discover
@@ -194,6 +222,7 @@ describe KubernetesService, models: true, caching: true do
 
   describe '#terminals' do
     let(:environment) { build(:environment, project: project, name: "env", slug: "env-000000") }
+
     subject { service.terminals(environment) }
 
     context 'with invalid pods' do
diff --git a/spec/support/kubernetes_helpers.rb b/spec/support/kubernetes_helpers.rb
index d2a1ded57ff..9280fad4ace 100644
--- a/spec/support/kubernetes_helpers.rb
+++ b/spec/support/kubernetes_helpers.rb
@@ -41,7 +41,7 @@ module KubernetesHelpers
     containers.map do |container|
       terminal = {
         selectors: { pod: pod_name, container: container['name'] },
-        url:  container_exec_url(service.api_url, service.namespace, pod_name, container['name']),
+        url:  container_exec_url(service.api_url, service.actual_namespace, pod_name, container['name']),
         subprotocols: ['channel.k8s.io'],
         headers: { 'Authorization' => ["Bearer #{service.token}"] },
         created_at: DateTime.parse(pod['metadata']['creationTimestamp']),