diff --git a/include/AudioStream.hpp b/include/AudioStream.hpp
index c018ea5e..a47a2a94 100644
--- a/include/AudioStream.hpp
+++ b/include/AudioStream.hpp
@@ -194,7 +194,7 @@ class AudioStream : public ::AudioStream {
     /**
      * Retrieve whether or not the audio stream is ready.
      */
-    bool IsReady() {
+    bool IsReady() const {
         return ::IsAudioStreamReady(*this);
     }
 
diff --git a/include/Font.hpp b/include/Font.hpp
index 3b49596c..be97d718 100644
--- a/include/Font.hpp
+++ b/include/Font.hpp
@@ -206,7 +206,7 @@ class Font : public ::Font {
     /**
      * Returns if the font is ready to be used.
      */
-    bool IsReady() {
+    bool IsReady() const {
         return ::IsFontReady(*this);
     }
 
diff --git a/include/Material.hpp b/include/Material.hpp
index e7c66fac..c9771061 100644
--- a/include/Material.hpp
+++ b/include/Material.hpp
@@ -112,7 +112,7 @@ class Material : public ::Material {
     /**
      * Check if material is ready
      */
-    inline bool IsReady() {
+    inline bool IsReady() const {
         return ::IsMaterialReady(*this);
     }
 
diff --git a/include/Rectangle.hpp b/include/Rectangle.hpp
index 661b1be0..08d208d1 100644
--- a/include/Rectangle.hpp
+++ b/include/Rectangle.hpp
@@ -109,11 +109,11 @@ class Rectangle : public ::Rectangle {
     /**
      * Check collision between circle and rectangle
      */
-    inline bool CheckCollision(::Vector2 center, float radius) {
+    inline bool CheckCollision(::Vector2 center, float radius) const {
         return ::CheckCollisionCircleRec(center, radius, *this);
     }
 
-    inline Vector2 GetSize() {
+    inline Vector2 GetSize() const {
         return {width, height};
     }
 
@@ -132,7 +132,7 @@ class Rectangle : public ::Rectangle {
         return *this;
     }
 
-    inline Vector2 GetPosition() {
+    inline Vector2 GetPosition() const {
         return {x, y};
     }
 
diff --git a/include/Text.hpp b/include/Text.hpp
index eba0a151..7e791f51 100644
--- a/include/Text.hpp
+++ b/include/Text.hpp
@@ -121,14 +121,14 @@ class Text {
     /**
      * Measure string width for default font
      */
-    inline int Measure() {
+    inline int Measure() const {
         return ::MeasureText(text.c_str(), static_cast<int>(fontSize));
     }
 
     /**
      * Measure string size for Font
      */
-    inline Vector2 MeasureEx() {
+    inline Vector2 MeasureEx() const {
         return ::MeasureTextEx(font, text.c_str(), fontSize, spacing);
     }