diff --git a/apis/dscinitialization/v1/dscinitialization_types.go b/apis/dscinitialization/v1/dscinitialization_types.go
index 7d71c52c995..e9598e89743 100644
--- a/apis/dscinitialization/v1/dscinitialization_types.go
+++ b/apis/dscinitialization/v1/dscinitialization_types.go
@@ -32,6 +32,7 @@ import (
 type DSCInitializationSpec struct {
 	// Namespace for applications to be installed, non-configurable, default to "opendatahub"
 	// +kubebuilder:default:=opendatahub
+	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="ApplicationsNamespace is immutable"
 	// +operator-sdk:csv:customresourcedefinitions:type=spec,order=1
 	ApplicationsNamespace string `json:"applicationsNamespace"`
 	// Enable monitoring on specified namespace
diff --git a/bundle/manifests/dscinitialization.opendatahub.io_dscinitializations.yaml b/bundle/manifests/dscinitialization.opendatahub.io_dscinitializations.yaml
index 67798e35b0e..5cb7b2a2d2f 100644
--- a/bundle/manifests/dscinitialization.opendatahub.io_dscinitializations.yaml
+++ b/bundle/manifests/dscinitialization.opendatahub.io_dscinitializations.yaml
@@ -57,6 +57,9 @@ spec:
                 description: Namespace for applications to be installed, non-configurable,
                   default to "opendatahub"
                 type: string
+                x-kubernetes-validations:
+                - message: ApplicationsNamespace is immutable
+                  rule: self == oldSelf
               devFlags:
                 description: |-
                   Internal development useful field to test customizations.
diff --git a/config/crd/bases/dscinitialization.opendatahub.io_dscinitializations.yaml b/config/crd/bases/dscinitialization.opendatahub.io_dscinitializations.yaml
index 0833b65acb0..edacd9cf82e 100644
--- a/config/crd/bases/dscinitialization.opendatahub.io_dscinitializations.yaml
+++ b/config/crd/bases/dscinitialization.opendatahub.io_dscinitializations.yaml
@@ -57,6 +57,9 @@ spec:
                 description: Namespace for applications to be installed, non-configurable,
                   default to "opendatahub"
                 type: string
+                x-kubernetes-validations:
+                - message: ApplicationsNamespace is immutable
+                  rule: self == oldSelf
               devFlags:
                 description: |-
                   Internal development useful field to test customizations.