diff --git a/src/SwaggerProvider.Runtime/RuntimeHelpers.fs b/src/SwaggerProvider.Runtime/RuntimeHelpers.fs
index e50f1e0d..9ee42e10 100644
--- a/src/SwaggerProvider.Runtime/RuntimeHelpers.fs
+++ b/src/SwaggerProvider.Runtime/RuntimeHelpers.fs
@@ -85,38 +85,42 @@ module RuntimeHelpers =
         | _ -> obj.ToString()
 
     let toQueryParams (name: string) (obj: obj) (client: Swagger.ProvidedApiClientBase) =
-        match obj with
-        | :? array<byte> as xs -> [ name, (client.Serialize xs).Trim('\"') ] // TODO: Need to verify how servers parse byte[] from query string
-        | :? array<bool> as xs -> xs |> toStrArray name
-        | :? array<int32> as xs -> xs |> toStrArray name
-        | :? array<int64> as xs -> xs |> toStrArray name
-        | :? array<float32> as xs -> xs |> toStrArray name
-        | :? array<double> as xs -> xs |> toStrArray name
-        | :? array<string> as xs -> xs |> toStrArray name
-        | :? array<DateTime> as xs -> xs |> toStrArrayDateTime name
-        | :? array<DateTimeOffset> as xs -> xs |> toStrArrayDateTimeOffset name
-        | :? array<Guid> as xs -> xs |> toStrArray name
-        | :? array<Option<bool>> as xs -> xs |> toStrArrayOpt name
-        | :? array<Option<int32>> as xs -> xs |> toStrArrayOpt name
-        | :? array<Option<int64>> as xs -> xs |> toStrArrayOpt name
-        | :? array<Option<float32>> as xs -> xs |> toStrArrayOpt name
-        | :? array<Option<double>> as xs -> xs |> toStrArrayOpt name
-        | :? array<Option<string>> as xs -> xs |> toStrArrayOpt name
-        | :? array<Option<DateTime>> as xs -> xs |> toStrArrayDateTimeOpt name
-        | :? array<Option<DateTimeOffset>> as xs -> xs |> toStrArrayDateTimeOffsetOpt name
-        | :? array<Option<Guid>> as xs -> xs |> toStrArray name
-        | :? Option<bool> as x -> x |> toStrOpt name
-        | :? Option<int32> as x -> x |> toStrOpt name
-        | :? Option<int64> as x -> x |> toStrOpt name
-        | :? Option<float32> as x -> x |> toStrOpt name
-        | :? Option<double> as x -> x |> toStrOpt name
-        | :? Option<string> as x -> x |> toStrOpt name
-        | :? Option<DateTime> as x -> x |> toStrDateTimeOpt name
-        | :? Option<DateTimeOffset> as x -> x |> toStrDateTimeOffsetOpt name
-        | :? DateTime as x -> [ name, x.ToString("O") ]
-        | :? DateTimeOffset as x -> [ name, x.ToString("O") ]
-        | :? Option<Guid> as x -> x |> toStrOpt name
-        | _ -> [ name, obj.ToString() ]
+        if isNull obj then
+            []
+        else
+
+            match obj with
+            | :? array<byte> as xs -> [ name, (client.Serialize xs).Trim('\"') ] // TODO: Need to verify how servers parse byte[] from query string
+            | :? array<bool> as xs -> xs |> toStrArray name
+            | :? array<int32> as xs -> xs |> toStrArray name
+            | :? array<int64> as xs -> xs |> toStrArray name
+            | :? array<float32> as xs -> xs |> toStrArray name
+            | :? array<double> as xs -> xs |> toStrArray name
+            | :? array<string> as xs -> xs |> toStrArray name
+            | :? array<DateTime> as xs -> xs |> toStrArrayDateTime name
+            | :? array<DateTimeOffset> as xs -> xs |> toStrArrayDateTimeOffset name
+            | :? array<Guid> as xs -> xs |> toStrArray name
+            | :? array<Option<bool>> as xs -> xs |> toStrArrayOpt name
+            | :? array<Option<int32>> as xs -> xs |> toStrArrayOpt name
+            | :? array<Option<int64>> as xs -> xs |> toStrArrayOpt name
+            | :? array<Option<float32>> as xs -> xs |> toStrArrayOpt name
+            | :? array<Option<double>> as xs -> xs |> toStrArrayOpt name
+            | :? array<Option<string>> as xs -> xs |> toStrArrayOpt name
+            | :? array<Option<DateTime>> as xs -> xs |> toStrArrayDateTimeOpt name
+            | :? array<Option<DateTimeOffset>> as xs -> xs |> toStrArrayDateTimeOffsetOpt name
+            | :? array<Option<Guid>> as xs -> xs |> toStrArray name
+            | :? Option<bool> as x -> x |> toStrOpt name
+            | :? Option<int32> as x -> x |> toStrOpt name
+            | :? Option<int64> as x -> x |> toStrOpt name
+            | :? Option<float32> as x -> x |> toStrOpt name
+            | :? Option<double> as x -> x |> toStrOpt name
+            | :? Option<string> as x -> x |> toStrOpt name
+            | :? Option<DateTime> as x -> x |> toStrDateTimeOpt name
+            | :? Option<DateTimeOffset> as x -> x |> toStrDateTimeOffsetOpt name
+            | :? DateTime as x -> [ name, x.ToString("O") ]
+            | :? DateTimeOffset as x -> [ name, x.ToString("O") ]
+            | :? Option<Guid> as x -> x |> toStrOpt name
+            | _ -> [ name, obj.ToString() ]
 
     let getPropertyNameAttribute name =
         { new Reflection.CustomAttributeData() with
diff --git a/tests/SwaggerProvider.Tests/RuntimeHelpersTests.fs b/tests/SwaggerProvider.Tests/RuntimeHelpersTests.fs
index 378f43fa..f6a9a3b6 100644
--- a/tests/SwaggerProvider.Tests/RuntimeHelpersTests.fs
+++ b/tests/SwaggerProvider.Tests/RuntimeHelpersTests.fs
@@ -152,8 +152,8 @@ module ToQueryParamsTests =
 
     [<Fact>]
     let ``toQueryParams returns empty list for null input (treated as Option None)``() =
-        // In F#, None for reference option types is compiled as null at the .NET level,
-        // so a null obj matches Option<string> None and returns an empty list.
+        // In F#, None for any option type is compiled as null at the .NET level,
+        // so a null obj is treated as Option None and returns an empty list.
         let result = toQueryParams "q" null stubClient
         result |> shouldEqual []