diff --git a/tests/accuracy.c b/tests/accuracy.c
index 01adbd1b..6a63c889 100644
--- a/tests/accuracy.c
+++ b/tests/accuracy.c
@@ -29,7 +29,6 @@
 //
 //========================================================================
 
-#define GLFW_INCLUDE_GLU
 #include <GLFW/glfw3.h>
 
 #include <stdio.h>
@@ -65,7 +64,7 @@ static void framebuffer_size_callback(GLFWwindow* window, int width, int height)
 
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
-    gluOrtho2D(0.f, window_width, 0.f, window_height);
+    glOrtho(0.f, window_width, 0.f, window_height, 0.f, 1.f);
 }
 
 static void cursor_position_callback(GLFWwindow* window, double x, double y)
diff --git a/tests/fsaa.c b/tests/fsaa.c
index 1725825c..459b7111 100644
--- a/tests/fsaa.c
+++ b/tests/fsaa.c
@@ -29,7 +29,6 @@
 //
 //========================================================================
 
-#define GLFW_INCLUDE_GLU
 #include <GLFW/glfw3.h>
 #include <GL/glext.h>
 
@@ -125,7 +124,7 @@ int main(int argc, char** argv)
         printf("Context reports FSAA is unavailable\n");
 
     glMatrixMode(GL_PROJECTION);
-    gluOrtho2D(0.f, 1.f, 0.f, 0.5f);
+    glOrtho(0.f, 1.f, 0.f, 0.5f, 0.f, 1.f);
     glMatrixMode(GL_MODELVIEW);
 
     while (!glfwWindowShouldClose(window))
diff --git a/tests/sharing.c b/tests/sharing.c
index 030ea110..54b15c81 100644
--- a/tests/sharing.c
+++ b/tests/sharing.c
@@ -27,7 +27,6 @@
 //
 //========================================================================
 
-#define GLFW_INCLUDE_GLU
 #include <GLFW/glfw3.h>
 
 #include <stdio.h>
@@ -100,7 +99,7 @@ static void draw_quad(GLuint texture)
 
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
-    gluOrtho2D(0.f, 1.f, 0.f, 1.f);
+    glOrtho(0.f, 1.f, 0.f, 1.f, 0.f, 1.f);
 
     glEnable(GL_TEXTURE_2D);
     glBindTexture(GL_TEXTURE_2D, texture);