diff --git a/src/plugins/intel_gpu/src/graph/impls/ocl/activation.cpp b/src/plugins/intel_gpu/src/graph/impls/ocl/activation.cpp
index 0f73af1e67fa..c7fbba04c675 100644
--- a/src/plugins/intel_gpu/src/graph/impls/ocl/activation.cpp
+++ b/src/plugins/intel_gpu/src/graph/impls/ocl/activation.cpp
@@ -89,6 +89,8 @@ attach_activation_impl::attach_activation_impl() {
      auto types = {
         data_types::f32,
         data_types::f16,
+        data_types::i16,
+        data_types::u16,
         data_types::i8,
         data_types::u8,
         data_types::i32
diff --git a/src/plugins/intel_gpu/src/kernel_selector/kernel_base.cpp b/src/plugins/intel_gpu/src/kernel_selector/kernel_base.cpp
index 83ab51f0a5ab..2bcef5d6d247 100644
--- a/src/plugins/intel_gpu/src/kernel_selector/kernel_base.cpp
+++ b/src/plugins/intel_gpu/src/kernel_selector/kernel_base.cpp
@@ -62,7 +62,7 @@ static bool IsTypeUsedIn(Datatype type, const base_params& params) {
 
 Datatype KernelBase::GetUnitType(const base_params& params) const {
     Datatype types_prioritized[] =
-        {Datatype::INT8, Datatype::F16, Datatype::INT32, Datatype::INT64, Datatype::UINT8, Datatype::UINT32};
+        {Datatype::INT8, Datatype::INT16, Datatype::UINT16, Datatype::F16, Datatype::INT32, Datatype::INT64, Datatype::UINT8, Datatype::UINT32};
 
     for (Datatype type : types_prioritized)
         if (IsTypeUsedIn(type, params))
diff --git a/src/plugins/intel_gpu/src/kernel_selector/kernels/activation/activation_kernel_ref.cpp b/src/plugins/intel_gpu/src/kernel_selector/kernels/activation/activation_kernel_ref.cpp
index 17aeee0d118f..c6c7d013fb56 100644
--- a/src/plugins/intel_gpu/src/kernel_selector/kernels/activation/activation_kernel_ref.cpp
+++ b/src/plugins/intel_gpu/src/kernel_selector/kernels/activation/activation_kernel_ref.cpp
@@ -13,11 +13,15 @@ ParamsKey ActivationKernelRef::GetSupportedKey() const {
     k.EnableInputDataType(Datatype::INT8);
     k.EnableInputDataType(Datatype::UINT8);
     k.EnableInputDataType(Datatype::INT32);
+    k.EnableInputDataType(Datatype::INT16);
+    k.EnableInputDataType(Datatype::UINT16);
     k.EnableInputDataType(Datatype::F16);
     k.EnableInputDataType(Datatype::F32);
     k.EnableOutputDataType(Datatype::INT8);
     k.EnableOutputDataType(Datatype::INT32);
     k.EnableOutputDataType(Datatype::UINT8);
+    k.EnableOutputDataType(Datatype::INT16);
+    k.EnableOutputDataType(Datatype::UINT16);
     k.EnableOutputDataType(Datatype::F16);
     k.EnableOutputDataType(Datatype::F32);
     k.EnableDifferentTypes();
diff --git a/src/plugins/intel_gpu/tests/unit/fusions/activation_fusion_test.cpp b/src/plugins/intel_gpu/tests/unit/fusions/activation_fusion_test.cpp
index 072a17827457..2b9120ee8aac 100644
--- a/src/plugins/intel_gpu/tests/unit/fusions/activation_fusion_test.cpp
+++ b/src/plugins/intel_gpu/tests/unit/fusions/activation_fusion_test.cpp
@@ -337,3 +337,45 @@ INSTANTIATE_TEST_SUITE_P(DISABLED_fusings_gpu, activation_eltwise_activation, ::
     activation_test_params{ CASE_ACTIVATION_3D_F32_4, 2, 4, "activation_ref" },  // FIXME - accuracy bug
     activation_test_params{ CASE_ACTIVATION_3D_F32_5, 2, 4, "activation_ref" },  // FIXME - accuracy bug
 }));
+
+TEST_F(ActivationFusingTest, reorder_activation_i16) {
+    // This tests CVS-188408: Ensure int16 Reorder -> Abs activation compiles cleanly
+    // Prior to fix, this would fail with CL_BUILD_PROGRAM_FAILURE due to "fabs" macro ambiguity.
+    auto& engine = get_test_engine();
+    ov::PartialShape input_shape = { 1, 4, 1, 1 };
+    layout in_layout{ input_shape, data_types::f32, format::bfyx };
+
+    topology topology(
+        input_layout("input", in_layout),
+        reorder("reorder", input_info("input"), format::bfyx, data_types::i16),
+        activation("abs", input_info("reorder"), activation_func::abs),
+        reorder("reorder_out", input_info("abs"), format::bfyx, data_types::f32)
+    );
+
+    ExecutionConfig config = get_test_default_config(engine);
+    config.set_property(ov::intel_gpu::allow_new_shape_infer(true));
+    config.set_property(ov::intel_gpu::optimize_data(true));
+    network network(engine, topology, config);
+
+    bool abs_fused = false;
+    for (const auto& pi : network.get_primitives_info()) {
+        for (const auto& fused_id : pi.c_fused_ids) {
+            if (fused_id == "abs") {
+                abs_fused = true;
+                break;
+            }
+        }
+        if (abs_fused)
+            break;
+    }
+    EXPECT_TRUE(abs_fused) << "Expected 'abs' to be fused when optimize_data(true)";
+
+    auto input_mem = engine.allocate_memory(in_layout);
+    set_values(input_mem, { -5.0f, 10.0f, -15.0f, 20.0f });
+    network.set_input_data("input", input_mem);
+    auto outputs = network.execute();
+    auto out_mem = outputs.at("reorder_out").get_memory();
+    cldnn::mem_lock<float> out_ptr(out_mem, get_test_stream());
+    std::vector<float> expected_output = { 5.0f, 10.0f, 15.0f, 20.0f };
+    for (size_t i = 0; i < expected_output.size(); ++i) { EXPECT_EQ(out_ptr[i], expected_output[i]); }
+}