diff --git a/src/codeflare_sdk/ray/cluster/build_ray_cluster.py b/src/codeflare_sdk/ray/cluster/build_ray_cluster.py
index e5526756a..e6aec3bd0 100644
--- a/src/codeflare_sdk/ray/cluster/build_ray_cluster.py
+++ b/src/codeflare_sdk/ray/cluster/build_ray_cluster.py
@@ -16,6 +16,7 @@
 This sub-module exists primarily to be used internally by the Cluster object
     (in the cluster sub-module) for RayCluster generation.
 """
+
 from typing import List, Union, Tuple, Dict
 from ...common import _kube_api_error_handling
 from ...common.kubernetes_cluster import get_api_client, config_check
@@ -54,6 +55,24 @@
 from codeflare_sdk.common.utils import constants
 
 FORBIDDEN_CUSTOM_RESOURCE_TYPES = ["GPU", "CPU", "memory"]
+
+
+def _cpu_limit_to_num_cpus(cpu_limit: Union[int, str]) -> str:
+    """Convert a Kubernetes CPU limit to an integer string for Ray's num-cpus.
+
+    Ray auto-detects host CPUs when num-cpus is not set, which can vastly
+    overcount in containerised environments (e.g. KinD on a beefy laptop).
+    Pinning num-cpus to the container CPU limit keeps the autoscaler's view
+    of available resources accurate.
+    """
+    if isinstance(cpu_limit, int):
+        return str(max(cpu_limit, 0))
+    s = str(cpu_limit).strip()
+    if s.endswith("m"):
+        return str(max(int(float(s[:-1]) / 1000), 1))
+    return str(max(int(float(s)), 1))
+
+
 VOLUME_MOUNTS = [
     V1VolumeMount(
         mount_path="/etc/pki/tls/certs/odh-trusted-ca-bundle.crt",
@@ -156,6 +175,7 @@ def build_ray_cluster(cluster: "codeflare_sdk.ray.cluster.Cluster"):
                 "rayStartParams": {
                     "dashboard-host": "0.0.0.0",
                     "block": "true",
+                    "num-cpus": _cpu_limit_to_num_cpus(cluster.config.head_cpu_limits),
                     "num-gpus": str(head_gpu_count),
                     "resources": head_resources,
                 },
@@ -180,6 +200,9 @@ def build_ray_cluster(cluster: "codeflare_sdk.ray.cluster.Cluster"):
                     "groupName": f"small-group-{cluster.config.name}",
                     "rayStartParams": {
                         "block": "true",
+                        "num-cpus": _cpu_limit_to_num_cpus(
+                            cluster.config.worker_cpu_limits
+                        ),
                         "num-gpus": str(worker_gpu_count),
                         "resources": worker_resources,
                     },
@@ -209,9 +232,9 @@ def build_ray_cluster(cluster: "codeflare_sdk.ray.cluster.Cluster"):
         gcs_ft_options = {"redisAddress": cluster.config.redis_address}
 
         if cluster.config.external_storage_namespace:
-            gcs_ft_options[
-                "externalStorageNamespace"
-            ] = cluster.config.external_storage_namespace
+            gcs_ft_options["externalStorageNamespace"] = (
+                cluster.config.external_storage_namespace
+            )
 
         if cluster.config.redis_password_secret:
             gcs_ft_options["redisPassword"] = {
@@ -456,28 +479,18 @@ def head_worker_extended_resources_from_cluster(
         resource_type = cluster.config.extended_resource_mapping[k]
         if resource_type in FORBIDDEN_CUSTOM_RESOURCE_TYPES:
             continue
-        head_worker_extended_resources[0][
-            resource_type
-        ] = cluster.config.head_extended_resource_requests[
-            k
-        ] + head_worker_extended_resources[
-            0
-        ].get(
-            resource_type, 0
+        head_worker_extended_resources[0][resource_type] = (
+            cluster.config.head_extended_resource_requests[k]
+            + head_worker_extended_resources[0].get(resource_type, 0)
         )
 
     for k in cluster.config.worker_extended_resource_requests.keys():
         resource_type = cluster.config.extended_resource_mapping[k]
         if resource_type in FORBIDDEN_CUSTOM_RESOURCE_TYPES:
             continue
-        head_worker_extended_resources[1][
-            resource_type
-        ] = cluster.config.worker_extended_resource_requests[
-            k
-        ] + head_worker_extended_resources[
-            1
-        ].get(
-            resource_type, 0
+        head_worker_extended_resources[1][resource_type] = (
+            cluster.config.worker_extended_resource_requests[k]
+            + head_worker_extended_resources[1].get(resource_type, 0)
         )
     return head_worker_extended_resources
 
diff --git a/src/codeflare_sdk/ray/cluster/test_build_ray_cluster.py b/src/codeflare_sdk/ray/cluster/test_build_ray_cluster.py
index cb1175c63..ec567f359 100644
--- a/src/codeflare_sdk/ray/cluster/test_build_ray_cluster.py
+++ b/src/codeflare_sdk/ray/cluster/test_build_ray_cluster.py
@@ -13,7 +13,12 @@
 # limitations under the License.
 from collections import namedtuple
 import sys
-from .build_ray_cluster import gen_names, update_image, build_ray_cluster
+from .build_ray_cluster import (
+    gen_names,
+    update_image,
+    build_ray_cluster,
+    _cpu_limit_to_num_cpus,
+)
 import uuid
 from codeflare_sdk.ray.cluster.cluster import ClusterConfiguration, Cluster
 
@@ -66,6 +71,19 @@ def test_update_image_without_supported_python_version(mocker):
     assert image is None
 
 
+def test_cpu_limit_to_num_cpus():
+    assert _cpu_limit_to_num_cpus(2) == "2"
+    assert _cpu_limit_to_num_cpus(0) == "0"
+    assert _cpu_limit_to_num_cpus(1) == "1"
+    assert _cpu_limit_to_num_cpus("500m") == "1"
+    assert _cpu_limit_to_num_cpus("1000m") == "1"
+    assert _cpu_limit_to_num_cpus("2000m") == "2"
+    assert _cpu_limit_to_num_cpus("250m") == "1"
+    assert _cpu_limit_to_num_cpus("1") == "1"
+    assert _cpu_limit_to_num_cpus("4") == "4"
+    assert _cpu_limit_to_num_cpus("8") == "8"
+
+
 def test_build_ray_cluster_with_gcs_ft(mocker):
     mocker.patch("kubernetes.config.load_kube_config", return_value="ignore")
     mocker.patch("kubernetes.client.CustomObjectsApi.list_namespaced_custom_object")
diff --git a/tests/e2e/autoscaling_load.py b/tests/e2e/autoscaling_load.py
new file mode 100644
index 000000000..6e4504248
--- /dev/null
+++ b/tests/e2e/autoscaling_load.py
@@ -0,0 +1,31 @@
+"""
+Workload used by E2E autoscaling tests.
+
+This script is submitted via Ray Job submission to generate enough queued work
+to trigger Ray in-tree autoscaling on a KinD cluster.
+"""
+
+import os
+import time
+
+import ray
+
+
+def main():
+    # Expect to run inside the Ray cluster environment (dashboard job submission)
+    ray.init(address="auto")
+
+    concurrency = int(os.getenv("AUTOSCALING_TASKS", "4"))
+    sleep_s = int(os.getenv("AUTOSCALING_TASK_SLEEP_S", "120"))
+
+    @ray.remote(num_cpus=1)
+    def burn_cpu():
+        time.sleep(sleep_s)
+        return True
+
+    futures = [burn_cpu.remote() for _ in range(concurrency)]
+    ray.get(futures)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tests/e2e/autoscaling_raycluster_sdk_kind_test.py b/tests/e2e/autoscaling_raycluster_sdk_kind_test.py
new file mode 100644
index 000000000..70c236d9e
--- /dev/null
+++ b/tests/e2e/autoscaling_raycluster_sdk_kind_test.py
@@ -0,0 +1,60 @@
+import pytest
+
+from codeflare_sdk import Cluster, ClusterConfiguration
+
+from support import *
+
+
+@pytest.mark.kind
+class TestRayClusterAutoscalingSDKKind:
+    def setup_method(self):
+        initialize_kubernetes_client(self)
+
+    def teardown_method(self):
+        delete_namespace(self)
+
+    def test_autoscaling_scale_up_and_down_kind(self):
+        self.setup_method()
+        create_namespace(self)
+
+        cluster_name = f"autoscale-{random_choice()}"
+        ray_image = get_ray_image()
+
+        cluster = Cluster(
+            ClusterConfiguration(
+                name=cluster_name,
+                namespace=self.namespace,
+                enable_autoscaling=True,
+                min_workers=1,
+                max_workers=2,
+                head_cpu_requests=1,
+                head_cpu_limits=1,
+                worker_cpu_requests=1,
+                worker_cpu_limits=1,
+                worker_memory_requests=1,
+                worker_memory_limits=4,
+                image=ray_image,
+                write_to_file=True,
+                verify_tls=False,
+            )
+        )
+
+        cluster.apply()
+        cluster.wait_ready(timeout=600, dashboard_check=False)
+
+        # Verify initial state: 1 worker (min_workers)
+        wait_for_worker_count(self, cluster_name, lambda n: n == 1, timeout_s=300)
+
+        # Trigger scale-up: 3 tasks @ 1 CPU each exceeds head(1) + worker(1) = 2 CPUs
+        load_proc = run_autoscaling_load_in_head_pod(self, cluster_name, tasks=3)
+
+        # Verify scale-up while load is still running
+        wait_for_worker_count(self, cluster_name, lambda n: n >= 2, timeout_s=600)
+
+        # Wait for load to finish, then verify scale-down back to min_workers
+        load_proc.wait(timeout=600)
+        assert load_proc.returncode == 0, "Load script failed"
+
+        wait_for_worker_count(self, cluster_name, lambda n: n == 1, timeout_s=600)
+
+        cluster.down()
diff --git a/tests/e2e/autoscaling_raycluster_sdk_oauth_test.py b/tests/e2e/autoscaling_raycluster_sdk_oauth_test.py
new file mode 100644
index 000000000..f5c4f8cac
--- /dev/null
+++ b/tests/e2e/autoscaling_raycluster_sdk_oauth_test.py
@@ -0,0 +1,65 @@
+import pytest
+
+from codeflare_sdk import Cluster, ClusterConfiguration
+
+from support import *
+
+
+@pytest.mark.openshift
+@pytest.mark.tier1
+class TestRayClusterAutoscalingSDKOauth:
+    def setup_method(self):
+        initialize_kubernetes_client(self)
+
+    def teardown_method(self):
+        if hasattr(self, "auth_instance"):
+            cleanup_authentication(self.auth_instance)
+        delete_namespace(self)
+
+    @pytest.mark.timeout(1800)
+    def test_autoscaling_scale_up_and_down_openshift_oauth(self):
+        self.setup_method()
+
+        create_namespace(self)
+
+        ray_image = get_ray_image()
+        resources = get_platform_appropriate_resources()
+        self.auth_instance = authenticate_for_tests()
+
+        cluster_name = f"autoscale-{random_choice()}"
+
+        cluster = Cluster(
+            ClusterConfiguration(
+                name=cluster_name,
+                namespace=self.namespace,
+                enable_autoscaling=True,
+                min_workers=1,
+                max_workers=2,
+                image=ray_image,
+                write_to_file=True,
+                verify_tls=False,
+                **resources,
+            )
+        )
+
+        cluster.apply()
+        wait_ready_with_stuck_detection(cluster, timeout=900, dashboard_check=False)
+
+        # Verify initial state: 1 worker (min_workers)
+        wait_for_worker_count(self, cluster_name, lambda n: n == 1, timeout_s=600)
+
+        # Trigger scale-up via load script in head pod (async)
+        load_proc = run_autoscaling_load_in_head_pod(
+            self, cluster_name, tasks=2, sleep_s=180
+        )
+
+        # Verify scale-up while load is still running
+        wait_for_worker_count(self, cluster_name, lambda n: n >= 2, timeout_s=900)
+
+        # Wait for load to finish, then verify scale-down back to min_workers
+        load_proc.wait(timeout=600)
+        assert load_proc.returncode == 0, "Load script failed"
+
+        wait_for_worker_count(self, cluster_name, lambda n: n == 1, timeout_s=900)
+
+        cluster.down()
diff --git a/tests/e2e/support.py b/tests/e2e/support.py
index 46f6c375b..a0642076a 100644
--- a/tests/e2e/support.py
+++ b/tests/e2e/support.py
@@ -2,8 +2,10 @@
 import random
 import string
 import subprocess
+import time
 import warnings
 from time import sleep
+
 from codeflare_sdk import get_cluster
 from kubernetes import client, config
 from kubernetes.client import V1Toleration
@@ -344,6 +346,66 @@ def run_kubectl_command(args):
         return None
 
 
+def wait_for_worker_count(self, cluster_name, predicate, timeout_s=600):
+    """Wait until the number of worker pods for cluster_name satisfies predicate."""
+    label = f"ray.io/node-type=worker,ray.io/cluster={cluster_name}"
+    start = time.time()
+    last = None
+    while time.time() - start < timeout_s:
+        pods = self.api_instance.list_namespaced_pod(
+            self.namespace, label_selector=label
+        )
+        last = len(pods.items or [])
+        if predicate(last):
+            return last
+        sleep(10)
+    raise TimeoutError(
+        f"Timed out waiting for worker count. cluster={cluster_name} last={last}"
+    )
+
+
+def run_autoscaling_load_in_head_pod(self, cluster_name, tasks=2, sleep_s=120):
+    """
+    Copy autoscaling_load.py into the head pod and run it asynchronously.
+    Returns the Popen handle so the caller can check for scale-up while
+    the workload is still running (avoids the race where blocking execution
+    lets workers scale back down before the assertion runs).
+    """
+    label = f"ray.io/node-type=head,ray.io/cluster={cluster_name}"
+    pods = self.api_instance.list_namespaced_pod(self.namespace, label_selector=label)
+    if not pods.items:
+        raise RuntimeError(f"No head pod found for cluster {cluster_name}")
+    head_pod = pods.items[0].metadata.name
+
+    load_script = os.path.join(
+        os.path.dirname(os.path.abspath(__file__)), "autoscaling_load.py"
+    )
+
+    subprocess.check_call(
+        [
+            "kubectl",
+            "cp",
+            load_script,
+            f"{self.namespace}/{head_pod}:/tmp/autoscaling_load.py",
+        ]
+    )
+
+    return subprocess.Popen(
+        [
+            "kubectl",
+            "exec",
+            "-n",
+            self.namespace,
+            head_pod,
+            "--",
+            "bash",
+            "-lc",
+            f"AUTOSCALING_TASKS={tasks} AUTOSCALING_TASK_SLEEP_S={sleep_s} "
+            f"python /tmp/autoscaling_load.py",
+        ]
+    )
+
+
 def create_cluster_queue(self, cluster_queue, flavor):
     cluster_queue_json = {
         "apiVersion": "kueue.x-k8s.io/v1beta1",
diff --git a/tests/test_cluster_yamls/kueue/ray_cluster_kueue.yaml b/tests/test_cluster_yamls/kueue/ray_cluster_kueue.yaml
index 66dfbdd7f..189720346 100644
--- a/tests/test_cluster_yamls/kueue/ray_cluster_kueue.yaml
+++ b/tests/test_cluster_yamls/kueue/ray_cluster_kueue.yaml
@@ -24,6 +24,7 @@ spec:
     rayStartParams:
       block: 'true'
       dashboard-host: 0.0.0.0
+      num-cpus: '2'
       num-gpus: '0'
       resources: '"{}"'
     serviceType: ClusterIP
@@ -92,6 +93,7 @@ spec:
     minReplicas: 2
     rayStartParams:
       block: 'true'
+      num-cpus: '4'
       num-gpus: '0'
       resources: '"{}"'
     replicas: 2
diff --git a/tests/test_cluster_yamls/ray/default-ray-cluster.yaml b/tests/test_cluster_yamls/ray/default-ray-cluster.yaml
index 024fc5ffd..51c1de267 100644
--- a/tests/test_cluster_yamls/ray/default-ray-cluster.yaml
+++ b/tests/test_cluster_yamls/ray/default-ray-cluster.yaml
@@ -23,6 +23,7 @@ spec:
     rayStartParams:
       block: 'true'
       dashboard-host: 0.0.0.0
+      num-cpus: '2'
       num-gpus: '0'
       resources: '"{}"'
     serviceType: ClusterIP
@@ -91,6 +92,7 @@ spec:
     minReplicas: 1
     rayStartParams:
       block: 'true'
+      num-cpus: '1'
       num-gpus: '0'
       resources: '"{}"'
     replicas: 1
diff --git a/tests/test_cluster_yamls/ray/unit-test-all-params.yaml b/tests/test_cluster_yamls/ray/unit-test-all-params.yaml
index 036b946ff..03952672f 100644
--- a/tests/test_cluster_yamls/ray/unit-test-all-params.yaml
+++ b/tests/test_cluster_yamls/ray/unit-test-all-params.yaml
@@ -30,6 +30,7 @@ spec:
     rayStartParams:
       block: 'true'
       dashboard-host: 0.0.0.0
+      num-cpus: '8'
       num-gpus: '1'
       resources: '"{\"TPU\": 2}"'
     serviceType: ClusterIP
@@ -137,6 +138,7 @@ spec:
     minReplicas: 10
     rayStartParams:
       block: 'true'
+      num-cpus: '8'
       num-gpus: '1'
       resources: '"{}"'
     replicas: 10