diff --git a/docs/docsite/rst/porting_guides/porting_guide_2.8.rst b/docs/docsite/rst/porting_guides/porting_guide_2.8.rst
index 266343a5b2a..091014a3586 100644
--- a/docs/docsite/rst/porting_guides/porting_guide_2.8.rst
+++ b/docs/docsite/rst/porting_guides/porting_guide_2.8.rst
@@ -112,6 +112,10 @@ add ``$ErrorActionPreference = "Continue"`` to the top of the module. This chang
 of the EAP that was accidentally removed in a previous release and ensure that modules are more resiliant to errors
 that may occur in execution.
 
+PowerShell module options and option choices are currently case insensitive to what is defined in the module
+specification. This behaviour is deprecated and a warning displayed to the user if a case insensitive match was found.
+A future release of Ansible will make these checks case sensitive.
+
 
 Modules removed
 ---------------
diff --git a/lib/ansible/module_utils/csharp/Ansible.Basic.cs b/lib/ansible/module_utils/csharp/Ansible.Basic.cs
index eee985e6a81..e5d99b2daa2 100644
--- a/lib/ansible/module_utils/csharp/Ansible.Basic.cs
+++ b/lib/ansible/module_utils/csharp/Ansible.Basic.cs
@@ -809,13 +809,18 @@ namespace Ansible.Basic
         private void CheckUnsupportedArguments(IDictionary param, List<string> legalInputs)
         {
             HashSet<string> unsupportedParameters = new HashSet<string>();
+            HashSet<string> caseUnsupportedParameters = new HashSet<string>();
             List<string> removedParameters = new List<string>();
 
             foreach (DictionaryEntry entry in param)
             {
                 string paramKey = (string)entry.Key;
-                if (!legalInputs.Contains(paramKey))
+                if (!legalInputs.Contains(paramKey, StringComparer.OrdinalIgnoreCase))
                     unsupportedParameters.Add(paramKey);
+                else if (!legalInputs.Contains(paramKey))
+                    // For backwards compatibility we do not care about the case but we need to warn the users as this will
+                    // change in a future Ansible release.
+                    caseUnsupportedParameters.Add(paramKey);
                 else if (paramKey.StartsWith("_ansible_"))
                 {
                     removedParameters.Add(paramKey);
@@ -852,6 +857,24 @@ namespace Ansible.Basic
                 msg = String.Format("{0}. Supported parameters include: {1}", FormatOptionsContext(msg), String.Join(", ", legalInputs));
                 FailJson(msg);
             }
+
+            if (caseUnsupportedParameters.Count > 0)
+            {
+                legalInputs.RemoveAll(x => passVars.Keys.Contains(x.Replace("_ansible_", "")));
+                string msg = String.Format("Parameters for ({0}) was a case insensitive match: {1}", ModuleName, String.Join(", ", caseUnsupportedParameters));
+                msg = String.Format("{0}. Module options will become case sensitive in a future Ansible release. Supported parameters include: {1}",
+                    FormatOptionsContext(msg), String.Join(", ", legalInputs));
+                Warn(msg);
+            }
+
+            // Make sure we convert all the incorrect case params to the ones set by the module spec
+            foreach (string key in caseUnsupportedParameters)
+            {
+                string correctKey = legalInputs[legalInputs.FindIndex(s => s.Equals(key, StringComparison.OrdinalIgnoreCase))];
+                object value = param[key];
+                param.Remove(key);
+                param.Add(correctKey, value);
+            }
         }
 
         private void CheckMutuallyExclusive(IDictionary param, IList mutuallyExclusive)
diff --git a/test/integration/targets/win_csharp_utils/library/ansible_basic_tests.ps1 b/test/integration/targets/win_csharp_utils/library/ansible_basic_tests.ps1
index 4b87c1160fc..8118a0f7264 100644
--- a/test/integration/targets/win_csharp_utils/library/ansible_basic_tests.ps1
+++ b/test/integration/targets/win_csharp_utils/library/ansible_basic_tests.ps1
@@ -503,6 +503,51 @@ $tests = @{
         $actual.invocation | Assert-DictionaryEquals -Expected @{module_args = $expected_module_args}
     }
 
+    "Parse module args with case insensitive input" = {
+        $spec = @{
+            options = @{
+                option1 = @{ type = "int"; required = $true }
+            }
+        }
+        $complex_args = @{
+            _ansible_module_name = "win_test"
+            Option1 = "1"
+        }
+
+        $m = [Ansible.Basic.AnsibleModule]::Create(@(), $spec)
+        # Verifies the case of the params key is set to the module spec not actual input
+        $m.Params.Keys | Assert-Equals -Expected @("option1")
+        $m.Params.option1 | Assert-Equals -Expected 1
+
+        # Verifies the type conversion happens even on a case insensitive match
+        $m.Params.option1.GetType().FullName | Assert-Equals -Expected "System.Int32"
+
+        $failed = $false
+        try {
+            $m.ExitJson()
+        } catch [System.Management.Automation.RuntimeException] {
+            $failed = $true
+            $_.Exception.Message | Assert-Equals -Expected "exit: 0"
+            $actual = [Ansible.Basic.AnsibleModule]::FromJson($_test_out)
+        }
+        $failed | Assert-Equals -Expected $true
+
+        $expected_warnings = "Parameters for (win_test) was a case insensitive match: Option1. "
+        $expected_warnings += "Module options will become case sensitive in a future Ansible release. "
+        $expected_warnings += "Supported parameters include: option1"
+
+        $expected = @{
+            changed = $false
+            invocation = @{
+                module_args = @{
+                    option1 = 1
+                }
+            }
+            warnings = @($expected_warnings)
+        }
+        $actual | Assert-DictionaryEquals -Expected $expected
+    }
+
     "No log values" = {
         $spec = @{
             options = @{