diff --git a/src/aks-preview/HISTORY.rst b/src/aks-preview/HISTORY.rst
index e46422f00d2..ce39e939566 100644
--- a/src/aks-preview/HISTORY.rst
+++ b/src/aks-preview/HISTORY.rst
@@ -12,6 +12,10 @@ To release a new version, please select a new version number (usually plus 1 to
 Pending
 +++++++
 
+17.0.0b3
+++++++++
+* Add default value of option `--vm-sizes` for `az aks create` and `az aks nodepool add`.
+
 17.0.0b2
 ++++++++
 * Add option `--migrate-vmas-to-vms` to `az aks update`
diff --git a/src/aks-preview/azext_aks_preview/_consts.py b/src/aks-preview/azext_aks_preview/_consts.py
index f0bee2788b7..9019bdc5729 100644
--- a/src/aks-preview/azext_aks_preview/_consts.py
+++ b/src/aks-preview/azext_aks_preview/_consts.py
@@ -46,6 +46,9 @@
 CONST_DEFAULT_NODE_VM_SIZE = ""
 CONST_DEFAULT_WINDOWS_NODE_VM_SIZE = ""
 
+CONST_DEFAULT_VMS_VM_SIZE = "Standard_DS2_v2"
+CONST_DEFAULT_WINDOWS_VMS_VM_SIZE = "Standard_D2s_v3"
+
 # workload runtime
 CONST_WORKLOAD_RUNTIME_OCI_CONTAINER = "OCIContainer"
 CONST_WORKLOAD_RUNTIME_WASM_WASI = "WasmWasi"
diff --git a/src/aks-preview/azext_aks_preview/agentpool_decorator.py b/src/aks-preview/azext_aks_preview/agentpool_decorator.py
index a7042745811..8e2c4467b86 100644
--- a/src/aks-preview/azext_aks_preview/agentpool_decorator.py
+++ b/src/aks-preview/azext_aks_preview/agentpool_decorator.py
@@ -37,6 +37,8 @@
     CONST_VIRTUAL_MACHINES,
     CONST_DEFAULT_NODE_VM_SIZE,
     CONST_DEFAULT_WINDOWS_NODE_VM_SIZE,
+    CONST_DEFAULT_VMS_VM_SIZE,
+    CONST_DEFAULT_WINDOWS_VMS_VM_SIZE,
     CONST_SSH_ACCESS_LOCALUSER,
 )
 from azext_aks_preview._helpers import (
@@ -714,6 +716,12 @@ def get_vm_sizes(self) -> List[str]:
             vm_sizes = [x.strip() for x in raw_value.split(",")]
         else:
             vm_sizes = [self.get_node_vm_size()]
+            # Populate default values if vm_sizes still empty
+            if vm_sizes == [""]:
+                if self.get_os_type().lower() == "windows":
+                    vm_sizes = [CONST_DEFAULT_WINDOWS_VMS_VM_SIZE]
+                else:
+                    vm_sizes = [CONST_DEFAULT_VMS_VM_SIZE]
         return vm_sizes
 
     # Overrides azure-cli command to allow changes after create
diff --git a/src/aks-preview/azext_aks_preview/tests/latest/test_agentpool_decorator.py b/src/aks-preview/azext_aks_preview/tests/latest/test_agentpool_decorator.py
index 0567d87ddd7..11ff1a0e0a6 100644
--- a/src/aks-preview/azext_aks_preview/tests/latest/test_agentpool_decorator.py
+++ b/src/aks-preview/azext_aks_preview/tests/latest/test_agentpool_decorator.py
@@ -30,6 +30,8 @@
 )
 from azext_aks_preview._consts import (
     CONST_DEFAULT_WINDOWS_NODE_VM_SIZE,
+    CONST_DEFAULT_VMS_VM_SIZE,
+    CONST_DEFAULT_WINDOWS_VMS_VM_SIZE,
 )
 from azure.cli.command_modules.acs.agentpool_decorator import AKSAgentPoolParamDict
 from azure.cli.command_modules.acs.tests.latest.mocks import (
@@ -804,7 +806,7 @@ def common_get_vm_sizes(self):
         )
         agentpool_1 = self.create_initialized_agentpool_instance(os_type="windows")
         ctx_1.attach_agentpool(agentpool_1)
-        self.assertEqual(ctx_1.get_vm_sizes(), [CONST_DEFAULT_WINDOWS_NODE_VM_SIZE])
+        self.assertEqual(ctx_1.get_vm_sizes(), [CONST_DEFAULT_WINDOWS_VMS_VM_SIZE])
 
         # default
         ctx_2 = AKSPreviewAgentPoolContext(
@@ -816,7 +818,7 @@ def common_get_vm_sizes(self):
         )
         agentpool_2 = self.create_initialized_agentpool_instance(os_type="linux")
         ctx_2.attach_agentpool(agentpool_2)
-        self.assertEqual(ctx_2.get_vm_sizes(), [CONST_DEFAULT_NODE_VM_SIZE], DeepDiff(ctx_2.get_vm_sizes(), [CONST_DEFAULT_NODE_VM_SIZE]))
+        self.assertEqual(ctx_2.get_vm_sizes(), [CONST_DEFAULT_VMS_VM_SIZE], DeepDiff(ctx_2.get_vm_sizes(), [CONST_DEFAULT_VMS_VM_SIZE]))
 
         # custom
         ctx_3 = AKSPreviewAgentPoolContext(
diff --git a/src/aks-preview/setup.py b/src/aks-preview/setup.py
index f616649c417..b394a642edf 100644
--- a/src/aks-preview/setup.py
+++ b/src/aks-preview/setup.py
@@ -9,7 +9,7 @@
 
 from setuptools import setup, find_packages
 
-VERSION = "17.0.0b2"
+VERSION = "17.0.0b3"
 
 CLASSIFIERS = [
     "Development Status :: 4 - Beta",