diff --git a/pkg/controller/operators/catalog/operator.go b/pkg/controller/operators/catalog/operator.go
index c26c3da927..24336fbd95 100644
--- a/pkg/controller/operators/catalog/operator.go
+++ b/pkg/controller/operators/catalog/operator.go
@@ -1654,12 +1654,6 @@ func (o *Operator) ensureInstallPlan(logger *logrus.Entry, namespace string, gen
 		return nil, nil
 	}
 
-	// Check if any existing installplans are creating the same resources
-	installPlans, err := o.listInstallPlans(namespace)
-	if err != nil {
-		return nil, err
-	}
-
 	// There are multiple(2) worker threads process the namespaceQueue.
 	// Both worker can work at the same time when 2 separate updates are made for the namespace.
 	// The following sequence causes 2 installplans are created for a subscription
@@ -1680,6 +1674,13 @@ func (o *Operator) ensureInstallPlan(logger *logrus.Entry, namespace string, gen
 	o.muInstallPlan.Lock()
 	defer o.muInstallPlan.Unlock()
 
+	// Check if any existing installplans are creating the same resources
+	// This must be done inside the lock to prevent TOCTOU race condition
+	installPlans, err := o.listInstallPlans(namespace)
+	if err != nil {
+		return nil, err
+	}
+
 	for _, installPlan := range installPlans {
 		if installPlan.Spec.Generation == gen {
 			return reference.GetReference(installPlan)
diff --git a/pkg/controller/operators/catalog/operator_test.go b/pkg/controller/operators/catalog/operator_test.go
index 00a6e48d9a..694a87ae94 100644
--- a/pkg/controller/operators/catalog/operator_test.go
+++ b/pkg/controller/operators/catalog/operator_test.go
@@ -9,6 +9,7 @@ import (
 	"os"
 	"reflect"
 	"strings"
+	"sync"
 	"testing"
 	"testing/quick"
 	"time"
@@ -2559,3 +2560,107 @@ func hasExpectedCondition(ip *v1alpha1.InstallPlan, expectedCondition v1alpha1.I
 	}
 	return false
 }
+
+// TestEnsureInstallPlanConcurrency tests that concurrent calls to ensureInstallPlan
+// do not create duplicate InstallPlans for the same subscription.
+// This test verifies the fix for a TOCTOU race condition where multiple worker threads
+// could create duplicate InstallPlans if they both check for existing plans before either
+// has created one.
+func TestEnsureInstallPlanConcurrency(t *testing.T) {
+	namespace := "test-ns"
+	gen := 1
+	numGoroutines := 10
+
+	ctx, cancel := context.WithCancel(context.TODO())
+	defer cancel()
+
+	// Create a fake operator
+	op, err := NewFakeOperator(ctx, namespace, []string{namespace})
+	require.NoError(t, err)
+
+	// Create a test subscription
+	sub := &v1alpha1.Subscription{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "test-sub",
+			Namespace: namespace,
+			UID:       types.UID("test-uid"),
+		},
+		Spec: &v1alpha1.SubscriptionSpec{
+			Package: "test-package",
+		},
+	}
+
+	// Create test steps for the InstallPlan
+	steps := []*v1alpha1.Step{
+		{
+			Resolving: "test-csv",
+			Resource: v1alpha1.StepResource{
+				CatalogSource:          "test-catalog",
+				CatalogSourceNamespace: namespace,
+				Group:                  "operators.coreos.com",
+				Version:                "v1alpha1",
+				Kind:                   "ClusterServiceVersion",
+				Name:                   "test-csv",
+				Manifest:               toManifest(t, csv("test-csv", namespace, nil, nil)),
+			},
+			Status: v1alpha1.StepStatusUnknown,
+		},
+	}
+
+	// Use WaitGroup to synchronize goroutines
+	var wg sync.WaitGroup
+	// Use a channel to collect results
+	results := make(chan *corev1.ObjectReference, numGoroutines)
+	// Use a sync.Once-like mechanism to start all goroutines at roughly the same time
+	startBarrier := make(chan struct{})
+
+	logger := logrus.NewEntry(logrus.New())
+
+	// Launch multiple goroutines that will call ensureInstallPlan concurrently
+	for i := 0; i < numGoroutines; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			// Wait for the start signal
+			<-startBarrier
+
+			// Call ensureInstallPlan
+			ref, err := op.ensureInstallPlan(logger, namespace, gen, []*v1alpha1.Subscription{sub}, v1alpha1.ApprovalAutomatic, steps, nil)
+			require.NoError(t, err)
+			results <- ref
+		}()
+	}
+
+	// Start all goroutines
+	close(startBarrier)
+
+	// Wait for all goroutines to complete
+	wg.Wait()
+	close(results)
+
+	// Collect all results
+	var refs []*corev1.ObjectReference
+	for ref := range results {
+		refs = append(refs, ref)
+	}
+
+	// Verify we got the expected number of results
+	require.Len(t, refs, numGoroutines, "should have received results from all goroutines")
+
+	// Verify all refs point to the same InstallPlan
+	firstRef := refs[0]
+	for i, ref := range refs {
+		require.Equal(t, firstRef.Name, ref.Name, "goroutine %d returned different InstallPlan name", i)
+		require.Equal(t, firstRef.Namespace, ref.Namespace, "goroutine %d returned different InstallPlan namespace", i)
+		require.Equal(t, firstRef.UID, ref.UID, "goroutine %d returned different InstallPlan UID", i)
+	}
+
+	// Verify only one InstallPlan was created in the cluster
+	ipList, err := op.client.OperatorsV1alpha1().InstallPlans(namespace).List(ctx, metav1.ListOptions{})
+	require.NoError(t, err)
+	require.Len(t, ipList.Items, 1, "exactly one InstallPlan should have been created")
+
+	// Verify the created InstallPlan has the correct generation
+	createdIP := &ipList.Items[0]
+	require.Equal(t, gen, createdIP.Spec.Generation, "InstallPlan should have the correct generation")
+}
diff --git a/pkg/controller/operators/olm/operator_test.go b/pkg/controller/operators/olm/operator_test.go
index fbaa32492a..6d0f1c679b 100644
--- a/pkg/controller/operators/olm/operator_test.go
+++ b/pkg/controller/operators/olm/operator_test.go
@@ -5853,6 +5853,12 @@ func RequireObjectsInCache(t *testing.T, lister operatorlister.OperatorLister, n
 			fetched, err = lister.RbacV1().RoleBindingLister().RoleBindings(namespace).Get(o.GetName())
 		case *v1alpha1.ClusterServiceVersion:
 			fetched, err = lister.OperatorsV1alpha1().ClusterServiceVersionLister().ClusterServiceVersions(namespace).Get(o.GetName())
+			if err != nil {
+				if apierrors.IsNotFound(err) {
+					return err
+				}
+				return errors.Join(err, fmt.Errorf("namespace: %v, error: %v", namespace, err))
+			}
 			// We don't care about finalizers
 			object.(*v1alpha1.ClusterServiceVersion).Finalizers = nil
 			fetched.(*v1alpha1.ClusterServiceVersion).Finalizers = nil