diff --git a/drivers/gles2/rasterizer_scene_gles2.cpp b/drivers/gles2/rasterizer_scene_gles2.cpp
index 107010a2d92..3e82bd33907 100644
--- a/drivers/gles2/rasterizer_scene_gles2.cpp
+++ b/drivers/gles2/rasterizer_scene_gles2.cpp
@@ -3192,6 +3192,7 @@ void RasterizerSceneGLES2::_post_process(Environment *env, const CameraMatrix &p
 		}
 	}
 
+	state.tonemap_shader.set_conditional(TonemapShaderGLES2::DISABLE_ALPHA, !storage->frame.current_rt->flags[RasterizerStorage::RENDER_TARGET_TRANSPARENT]);
 	state.tonemap_shader.bind();
 	if (env) {
 		if (max_glow_level >= 0) {
@@ -3230,6 +3231,7 @@ void RasterizerSceneGLES2::_post_process(Environment *env, const CameraMatrix &p
 	state.tonemap_shader.set_conditional(TonemapShaderGLES2::USE_MULTI_TEXTURE_GLOW, false);
 	state.tonemap_shader.set_conditional(TonemapShaderGLES2::USE_BCS, false);
 	state.tonemap_shader.set_conditional(TonemapShaderGLES2::USE_COLOR_CORRECTION, false);
+	state.tonemap_shader.set_conditional(TonemapShaderGLES2::DISABLE_ALPHA, false);
 }
 
 void RasterizerSceneGLES2::render_scene(const Transform &p_cam_transform, const CameraMatrix &p_cam_projection, const int p_eye, bool p_cam_ortogonal, InstanceBase **p_cull_result, int p_cull_count, RID *p_light_cull_result, int p_light_cull_count, RID *p_reflection_probe_cull_result, int p_reflection_probe_cull_count, RID p_environment, RID p_shadow_atlas, RID p_reflection_atlas, RID p_reflection_probe, int p_reflection_probe_pass) {
diff --git a/drivers/gles2/shaders/tonemap.glsl b/drivers/gles2/shaders/tonemap.glsl
index aaa6ae5498f..a35826642b3 100644
--- a/drivers/gles2/shaders/tonemap.glsl
+++ b/drivers/gles2/shaders/tonemap.glsl
@@ -357,4 +357,8 @@ void main() {
 #endif
 
 	gl_FragColor = color;
+
+#ifdef DISABLE_ALPHA
+	gl_FragColor.a = 1.0;
+#endif
 }
diff --git a/drivers/gles3/rasterizer_scene_gles3.cpp b/drivers/gles3/rasterizer_scene_gles3.cpp
index c6641e1bc6f..f1d21a0865e 100644
--- a/drivers/gles3/rasterizer_scene_gles3.cpp
+++ b/drivers/gles3/rasterizer_scene_gles3.cpp
@@ -4001,6 +4001,7 @@ void RasterizerSceneGLES3::_post_process(Environment *env, const CameraMatrix &p
 		}
 	}
 
+	state.tonemap_shader.set_conditional(TonemapShaderGLES3::DISABLE_ALPHA, !storage->frame.current_rt->flags[RasterizerStorage::RENDER_TARGET_TRANSPARENT]);
 	state.tonemap_shader.set_conditional(TonemapShaderGLES3::V_FLIP, storage->frame.current_rt->flags[RasterizerStorage::RENDER_TARGET_VFLIP]);
 	state.tonemap_shader.bind();
 
@@ -4064,6 +4065,7 @@ void RasterizerSceneGLES3::_post_process(Environment *env, const CameraMatrix &p
 	state.tonemap_shader.set_conditional(TonemapShaderGLES3::USE_BCS, false);
 	state.tonemap_shader.set_conditional(TonemapShaderGLES3::USE_COLOR_CORRECTION, false);
 	state.tonemap_shader.set_conditional(TonemapShaderGLES3::V_FLIP, false);
+	state.tonemap_shader.set_conditional(TonemapShaderGLES3::DISABLE_ALPHA, false);
 }
 
 bool RasterizerSceneGLES3::_element_needs_directional_add(RenderList::Element *e) {
diff --git a/drivers/gles3/shaders/tonemap.glsl b/drivers/gles3/shaders/tonemap.glsl
index f2639772ce6..5f160e22eca 100644
--- a/drivers/gles3/shaders/tonemap.glsl
+++ b/drivers/gles3/shaders/tonemap.glsl
@@ -489,4 +489,8 @@ void main() {
 #endif
 
 	frag_color = color;
+
+#ifdef DISABLE_ALPHA
+	frag_color.a = 1.0;
+#endif
 }