diff --git a/pkg/controllers/monitoring/monitoring-stack/alertmanager.go b/pkg/controllers/monitoring/monitoring-stack/alertmanager.go
index 3f512e468..e19f6f72e 100644
--- a/pkg/controllers/monitoring/monitoring-stack/alertmanager.go
+++ b/pkg/controllers/monitoring/monitoring-stack/alertmanager.go
@@ -36,6 +36,7 @@ func newAlertmanager(
 				Labels: podLabels("alertmanager", ms.Name),
 			},
 			Replicas:                   ms.Spec.AlertmanagerConfig.Replicas,
+			Resources:                  ms.Spec.Resources,
 			ServiceAccountName:         rbacResourceName,
 			AlertmanagerConfigSelector: resourceSelector,
 			NodeSelector:               ms.Spec.NodeSelector,
diff --git a/pkg/controllers/monitoring/monitoring-stack/components.go b/pkg/controllers/monitoring/monitoring-stack/components.go
index 8c7957b39..889ea074e 100644
--- a/pkg/controllers/monitoring/monitoring-stack/components.go
+++ b/pkg/controllers/monitoring/monitoring-stack/components.go
@@ -214,7 +214,8 @@ func newPrometheus(
 			RuleSelector:          prometheusSelector,
 			RuleNamespaceSelector: ms.Spec.NamespaceSelector,
 			Thanos: &monv1.ThanosSpec{
-				Image: ptr.To(thanosCfg.Image),
+				Image:     ptr.To(thanosCfg.Image),
+				Resources: ms.Spec.Resources,
 			},
 		},
 	}
diff --git a/pkg/controllers/monitoring/monitoring-stack/components_test.go b/pkg/controllers/monitoring/monitoring-stack/components_test.go
index e5feee830..320f8b87a 100644
--- a/pkg/controllers/monitoring/monitoring-stack/components_test.go
+++ b/pkg/controllers/monitoring/monitoring-stack/components_test.go
@@ -46,6 +46,63 @@ func TestStorageSpec(t *testing.T) {
 	}
 }
 
+func TestNewAlertmanagerSetsResources(t *testing.T) {
+	resources := corev1.ResourceRequirements{
+		Requests: corev1.ResourceList{
+			corev1.ResourceCPU:    resource.MustParse("100m"),
+			corev1.ResourceMemory: resource.MustParse("256Mi"),
+		},
+		Limits: corev1.ResourceList{
+			corev1.ResourceCPU:    resource.MustParse("500m"),
+			corev1.ResourceMemory: resource.MustParse("512Mi"),
+		},
+	}
+	ms := &stack.MonitoringStack{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "test",
+			Namespace: "ns",
+		},
+		Spec: stack.MonitoringStackSpec{
+			Resources:          resources,
+			AlertmanagerConfig: stack.AlertmanagerConfig{},
+		},
+	}
+
+	am := newAlertmanager(ms, "test-alertmanager", AlertmanagerConfiguration{})
+	assert.DeepEqual(t, resources, am.Spec.Resources)
+}
+
+func TestNewPrometheusSetsThanosSidecarResources(t *testing.T) {
+	resources := corev1.ResourceRequirements{
+		Requests: corev1.ResourceList{
+			corev1.ResourceCPU:    resource.MustParse("100m"),
+			corev1.ResourceMemory: resource.MustParse("256Mi"),
+		},
+		Limits: corev1.ResourceList{
+			corev1.ResourceCPU:    resource.MustParse("500m"),
+			corev1.ResourceMemory: resource.MustParse("512Mi"),
+		},
+	}
+	ms := &stack.MonitoringStack{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "test",
+			Namespace: "ns",
+		},
+		Spec: stack.MonitoringStackSpec{
+			Resources:          resources,
+			PrometheusConfig:   &stack.PrometheusConfig{},
+			AlertmanagerConfig: stack.AlertmanagerConfig{Disabled: true},
+		},
+	}
+
+	prom := newPrometheus(ms, "test-prometheus", "test-scrape",
+		ThanosConfiguration{Image: "thanos:latest"},
+		PrometheusConfiguration{})
+
+	assert.DeepEqual(t, resources, prom.Spec.Thanos.Resources)
+	assert.DeepEqual(t, resources, prom.Spec.Resources)
+}
+
 func TestNewAdditionalScrapeConfigsSecret(t *testing.T) {
 	for _, tc := range []struct {
 		name       string