diff --git a/cmd/antrea-agent/options.go b/cmd/antrea-agent/options.go
index 133240c70a5..7e1ec94de2b 100644
--- a/cmd/antrea-agent/options.go
+++ b/cmd/antrea-agent/options.go
@@ -604,6 +604,12 @@ func (o *Options) validateK8sNodeOptions() error {
 		return fmt.Errorf("failed to validate secondary network config: %v", err)
 	}
 
+	// Unlike checkUnsupportedFeatures, validateConfigForPlatform runs after all validations and
+	// after all fields in the Options struct have been initialized (e.g., enableProxy).
+	if err := o.validateConfigForPlatform(); err != nil {
+		return err
+	}
+
 	return nil
 }
 
diff --git a/cmd/antrea-agent/options_linux.go b/cmd/antrea-agent/options_linux.go
index ec117056a59..9f1856b13f8 100644
--- a/cmd/antrea-agent/options_linux.go
+++ b/cmd/antrea-agent/options_linux.go
@@ -25,3 +25,8 @@ func (o *Options) checkUnsupportedFeatures() error {
 	// All features are supported on a Linux Node.
 	return nil
 }
+
+func (o *Options) validateConfigForPlatform() error {
+	// No additional validations for Linux Nodes.
+	return nil
+}
diff --git a/cmd/antrea-agent/options_windows.go b/cmd/antrea-agent/options_windows.go
index 2238c764021..92075d4fac4 100644
--- a/cmd/antrea-agent/options_windows.go
+++ b/cmd/antrea-agent/options_windows.go
@@ -64,8 +64,24 @@ func (o *Options) checkUnsupportedFeatures() error {
 		return fmt.Errorf("unsupported features on Windows: {%s}", strings.Join(unsupported, ", "))
 	}
 
+	return nil
+}
+
+func (o *Options) validateConfigForPlatform() error {
+	// AntreaProxy with proxyAll is required on Windows.
+	// The userspace kube-proxy mode (only mode compatible with the Antrea Agent on Windows) was
+	// removed in K8s v1.26, hence the requirement for proxyAll.
+	// Even prior to that, AntreaProxy was required for correct NetworkPolicy enforcement for
+	// Service traffic.
+	// While we do not fail initialization at the moment, there should be no valid use case for
+	// Antrea on Windows without AntreaProxy + proxyAll.
 	if !o.enableAntreaProxy {
-		klog.Warning("AntreaProxy is not enabled. NetworkPolicies might not be enforced correctly for Service traffic!")
+		klog.ErrorS(nil, "AntreaProxy is disabled, Service traffic is unlikely to work as expected")
+		return nil
+	}
+	if !o.config.AntreaProxy.ProxyAll {
+		klog.ErrorS(nil, "AntreaProxy proxyAll is disabled, Service traffic is unlikely to work as expected")
+		return nil
 	}
 	return nil
 }