diff --git a/providers/openfeature-flagd-provider/lib/openfeature/flagd/provider/client.rb b/providers/openfeature-flagd-provider/lib/openfeature/flagd/provider/client.rb
index 47db1a6..56fa3cd 100644
--- a/providers/openfeature-flagd-provider/lib/openfeature/flagd/provider/client.rb
+++ b/providers/openfeature-flagd-provider/lib/openfeature/flagd/provider/client.rb
@@ -98,7 +98,7 @@ def prepare_evaluation_context(evaluation_context)
           return nil unless evaluation_context
 
           fields = evaluation_context.fields
-          fields["targetingKey"] = fields.delete(:targeting_key)
+          fields["targetingKey"] = fields.delete("targeting_key")
           Google::Protobuf::Struct.from_hash(fields)
         end
 
diff --git a/providers/openfeature-flagd-provider/spec/openfeature/flagd/provider/client_spec.rb b/providers/openfeature-flagd-provider/spec/openfeature/flagd/provider/client_spec.rb
index 258f6a2..2d2687d 100644
--- a/providers/openfeature-flagd-provider/spec/openfeature/flagd/provider/client_spec.rb
+++ b/providers/openfeature-flagd-provider/spec/openfeature/flagd/provider/client_spec.rb
@@ -92,4 +92,26 @@
       )
     end
   end
+
+  context "EvaluationContext transformation" do
+    subject { client.send(:prepare_evaluation_context, evaluation_context) }
+    let(:evaluation_context) { OpenFeature::SDK::EvaluationContext.new(**fields) }
+
+    context "No context" do
+      let(:evaluation_context) { nil }
+
+      it do
+        expect(subject).to be nil
+      end
+    end
+
+    context "targeting_key transformation to targetingKey" do
+      let(:fields) { {targeting_key: "example"} }
+      let(:expected) { Google::Protobuf::Struct.from_hash({targetingKey: "example"}.transform_keys(&:to_s)) }
+
+      it do
+        expect(subject).to eq(expected)
+      end
+    end
+  end
 end