diff --git a/modules/openapi-generator/src/main/resources/powershell/api_client.mustache b/modules/openapi-generator/src/main/resources/powershell/api_client.mustache
index b17371ad1e37..7d45f071b1e6 100644
--- a/modules/openapi-generator/src/main/resources/powershell/api_client.mustache
+++ b/modules/openapi-generator/src/main/resources/powershell/api_client.mustache
@@ -211,6 +211,10 @@ function DeserializeResponse {
         [string[]]$ContentTypes
     )
 
+    If ($ContentTypes -eq $null) {
+        $ContentTypes = [string[]]@()
+    }
+
     If ([string]::IsNullOrEmpty($ReturnType) -and $ContentTypes.Count -eq 0) { # void response
         return $Response
     } Elseif ($ReturnType -match '\[\]$') { # array
diff --git a/samples/client/petstore/powershell/src/PSPetstore/Private/PSApiClient.ps1 b/samples/client/petstore/powershell/src/PSPetstore/Private/PSApiClient.ps1
index 9223b3a93e61..09a202cee9df 100644
--- a/samples/client/petstore/powershell/src/PSPetstore/Private/PSApiClient.ps1
+++ b/samples/client/petstore/powershell/src/PSPetstore/Private/PSApiClient.ps1
@@ -198,6 +198,10 @@ function DeserializeResponse {
         [string[]]$ContentTypes
     )
 
+    If ($ContentTypes -eq $null) {
+        $ContentTypes = [string[]]@()
+    }
+
     If ([string]::IsNullOrEmpty($ReturnType) -and $ContentTypes.Count -eq 0) { # void response
         return $Response
     } Elseif ($ReturnType -match '\[\]$') { # array