diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2ae5413..fa19780 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -35,6 +35,7 @@ set(LUNARIUM_SRC
 "src/graphics/internalFont.cpp"
 "src/input/keyboard.cpp"
 "src/input/inputManager.cpp"
+"src/graphics/gui/gui.cpp"
 )
 
 # add the executable
diff --git a/src/core/core.cpp b/src/core/core.cpp
index db86bc4..4ce5495 100644
--- a/src/core/core.cpp
+++ b/src/core/core.cpp
@@ -12,12 +12,14 @@
 // Sub Systems
 #include <window/window.h>
 #include <graphics/opengl/glGraphics.h>
+#include <graphics/gui/gui.h>
 
 namespace lunarium
 {
     Core* Core::mpInstance = nullptr;
     Core::Core()
-        : mbIsInit(false), mpArgs(nullptr), mpWindow(nullptr), mpGraphics(nullptr), mpInput(nullptr)
+        : mbIsInit(false), mpArgs(nullptr), mpWindow(nullptr), mpGraphics(nullptr), mpInput(nullptr),
+        mGUI(GUI::GetInstance())
     {
     
     }
@@ -40,6 +42,9 @@ namespace lunarium
         Logger::Log(LogCategory::CORE, LogLevel::INFO, "Lunarium is shutting down!");
 
         // Shutdown subsystems
+        GUI::GetInstance().Shutdown();
+        GUI::FreeInstance();
+
         mpInstance->mpInput->Shutdown();
         delete mpInstance->mpInput;
         mpInstance->mpInput = nullptr;
@@ -144,6 +149,9 @@ namespace lunarium
         mpInput = new InputManager;
         mpInput->Initialize(mpWindow);
 
+        // GUI
+        mGUI.Initialize(mpWindow);
+
         mbIsInit = true;
     }
 
@@ -196,8 +204,12 @@ namespace lunarium
             // Update game state
 
             // Render
+            mGUI.NewFrame();
             mpGraphics->BeginDraw();
 
+            // DEBUG: Render test ImGUI window
+            mGUI.ShowDemoWindow();
+
             // DEBUG: Graphics tests
             mpGraphics->DrawFilledEllipse(glm::vec2(600, 300), glm::vec2(100, 150), Color(1.0f, 0.0f, 1.0f, 1.0f), 100);
             mpGraphics->DrawString("This is a test of the text renderer!", Rectangle(100, 200, width, 300), 
diff --git a/src/core/core.h b/src/core/core.h
index 92c298f..f8d480f 100644
--- a/src/core/core.h
+++ b/src/core/core.h
@@ -17,6 +17,7 @@
 
 namespace lunarium
 {
+    class GUI;
     class IGraphics;
     class Window;
 
@@ -51,6 +52,7 @@ namespace lunarium
     Window*         mpWindow;
     IGraphics*      mpGraphics;
     InputManager*   mpInput;
+    GUI&            mGUI;
 
     InputManager::_KeyEvents mKeyEvents;
 
diff --git a/src/graphics/gui/gui.cpp b/src/graphics/gui/gui.cpp
new file mode 100644
index 0000000..38ad4f3
--- /dev/null
+++ b/src/graphics/gui/gui.cpp
@@ -0,0 +1,117 @@
+/******************************************************************************
+*	File		-	gui.cpp
+*	Author		-	Joey Pollack
+*	Date		-	2021/09/09 (y/m/d)
+*	Mod Date	-	2021/09/09 (y/m/d)
+*	Description	-	The main class that manages Dear ImGui
+******************************************************************************/
+
+#include "gui.h"
+
+#include <window/window.h>
+#include <utils/helpers.h>
+#include <utils/logger.h>
+#include <imgui.h>
+#include <imgui_impl_glfw.h>
+#include <imgui_impl_opengl3.h>
+
+namespace lunarium
+{
+    GUI* GUI::mpInstance = nullptr;
+    GUI::GUI()
+        : mbIsInit(false), mbShowDemo(false)
+    {
+
+    }
+
+    GUI& GUI::GetInstance()
+    {
+        if (!mpInstance)
+        {
+            mpInstance = new GUI;
+        }
+
+        return *mpInstance;
+    }
+
+    void GUI::FreeInstance()
+    {
+        delete mpInstance;
+        mpInstance = nullptr;
+    }
+
+    OpRes GUI::Initialize(Window* pWindow)
+    {
+        if (mbIsInit)
+        {
+            return OpRes::Fail("GUI is already initialized!");
+        }
+
+        IMGUI_CHECKVERSION();
+        ImGui::CreateContext();
+        ImGuiIO& io = ImGui::GetIO(); (void)io;
+        io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;       // Enable Keyboard Controls
+        //io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+        io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;           // Enable Docking
+        io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;         // Enable Multi-Viewport / Platform Windows
+
+        // Setup Dear ImGui style
+        ImGui::StyleColorsDark();
+
+        // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+        ImGuiStyle& style = ImGui::GetStyle();
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            style.WindowRounding = 0.0f;
+            style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+        }
+
+        // Setup Platform/Renderer backends
+        ImGui_ImplGlfw_InitForOpenGL(pWindow->GetWindow(), true);
+        ImGui_ImplOpenGL3_Init(System::GetGLSLVersionString().c_str());
+
+        // Our state
+        ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
+        mbShowDemo = true;
+
+        Logger::Log(LogCategory::GRAPHICS, LogLevel::INFO, "ImGui setup");
+        return OpRes::OK();
+    }
+
+    void GUI::Shutdown()
+    {
+        ImGui_ImplOpenGL3_Shutdown();
+        ImGui_ImplGlfw_Shutdown();
+        ImGui::DestroyContext();
+
+        mbIsInit = false;
+    }
+
+    void GUI::NewFrame()
+    {
+        if (!mbIsInit)
+            return;
+
+        ImGui_ImplOpenGL3_NewFrame();
+        ImGui_ImplGlfw_NewFrame();
+        ImGui::NewFrame();
+    }
+
+    void GUI::ShowDemoWindow()
+    {
+        if (!mbIsInit)
+            return;
+            
+        ImGui::ShowDemoWindow(&mbShowDemo);       
+        ImGui::Render();
+        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
+        if (ImGui::GetIO().ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+        {
+            GLFWwindow* backup_current_context = glfwGetCurrentContext();
+            ImGui::UpdatePlatformWindows();
+            ImGui::RenderPlatformWindowsDefault();
+            glfwMakeContextCurrent(backup_current_context);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/graphics/gui/gui.h b/src/graphics/gui/gui.h
new file mode 100644
index 0000000..235fdcf
--- /dev/null
+++ b/src/graphics/gui/gui.h
@@ -0,0 +1,40 @@
+/******************************************************************************
+*	File		-	gui.h
+*	Author		-	Joey Pollack
+*	Date		-	2021/09/09 (y/m/d)
+*	Mod Date	-	2021/09/09 (y/m/d)
+*	Description	-	The main class that manages Dear ImGui
+******************************************************************************/
+
+#ifndef GUI_H_
+#define GUI_H_
+
+#include <utils/opRes.h>
+
+namespace lunarium
+{
+    class Window;
+    class GUI
+    {
+    public:
+        static GUI& GetInstance();
+        static void FreeInstance();
+        OpRes Initialize(Window* pWindow);
+        void Shutdown();
+
+        void NewFrame();
+        void ShowDemoWindow();
+
+    private:
+        GUI();
+        GUI(const GUI&) = delete;
+        const GUI operator=(const GUI&) = delete;
+
+    private:
+        static GUI* mpInstance;
+        bool mbIsInit;
+        bool mbShowDemo;
+    };
+}
+
+#endif // GIU_H_
\ No newline at end of file
diff --git a/src/test_main.cpp b/src/test_main.cpp
index 686bc06..e774d6a 100644
--- a/src/test_main.cpp
+++ b/src/test_main.cpp
@@ -7,7 +7,7 @@
 #include <imgui_impl_opengl3.h>
 #include <pugixml.hpp>
 #include "utils/logger.h"
-#include "utilsoOpRes.h"
+#include "utils/OpRes.h"
 #include "core/state.h"
 #include "core/version.h"
 #include "utils/args.h"