diff --git a/src/back/glsl/mod.rs b/src/back/glsl/mod.rs
index 985c385c0..6a4147149 100644
--- a/src/back/glsl/mod.rs
+++ b/src/back/glsl/mod.rs
@@ -106,7 +106,7 @@ impl Version {
 
     /// Checks if the version supports explicit `layout(location=)` qualifiers.
     fn supports_explicit_locations(&self) -> bool {
-        *self >= Version::Embedded(310) || *self >= Version::Desktop(410)
+        *self >= Version::Embedded(300) || *self >= Version::Desktop(410)
     }
 }
 
@@ -825,7 +825,9 @@ impl<'a, W: Write> Writer<'a, W> {
                 }
 
                 // Write the storage class
-                if self.options.version.supports_explicit_locations() {
+                if !emit_interpolation_and_auxiliary
+                    && self.options.version.supports_explicit_locations()
+                {
                     write!(self.out, "layout(location = {}) ", location)?;
                 }
 
diff --git a/tests/out/quad-vert.Vertex.glsl b/tests/out/quad-vert.Vertex.glsl
index c2f59e712..40d321619 100644
--- a/tests/out/quad-vert.Vertex.glsl
+++ b/tests/out/quad-vert.Vertex.glsl
@@ -21,7 +21,7 @@ struct gen_gl_PerVertex_block_0 {
 vec2 a_pos = vec2(0, 0);
 layout(location = 1) in vec2 _p2vs_location1;
 layout(location = 0) in vec2 _p2vs_location0;
-smooth layout(location = 0) out vec2 _vs2fs_location0;
+smooth out vec2 _vs2fs_location0;
 
 void main1() {
     v_uv = a_uv;
diff --git a/tests/out/quad.Fragment.glsl b/tests/out/quad.Fragment.glsl
index 825f9bd4d..ff24336cf 100644
--- a/tests/out/quad.Fragment.glsl
+++ b/tests/out/quad.Fragment.glsl
@@ -9,7 +9,7 @@ struct VertexOutput {
 
 uniform highp sampler2D _group_0_binding_0;
 
-smooth layout(location = 0) in vec2 _vs2fs_location0;
+smooth in vec2 _vs2fs_location0;
 layout(location = 0) out vec4 _fs2p_location0;
 
 void main() {
diff --git a/tests/out/quad.Vertex.glsl b/tests/out/quad.Vertex.glsl
index 95ce41427..873bbf39b 100644
--- a/tests/out/quad.Vertex.glsl
+++ b/tests/out/quad.Vertex.glsl
@@ -9,7 +9,7 @@ struct VertexOutput {
 
 layout(location = 0) in vec2 _p2vs_location0;
 layout(location = 1) in vec2 _p2vs_location1;
-smooth layout(location = 0) out vec2 _vs2fs_location0;
+smooth out vec2 _vs2fs_location0;
 
 void main() {
     vec2 pos = _p2vs_location0;
diff --git a/tests/out/shadow.Fragment.glsl b/tests/out/shadow.Fragment.glsl
index 5b9c58de0..df9f71c64 100644
--- a/tests/out/shadow.Fragment.glsl
+++ b/tests/out/shadow.Fragment.glsl
@@ -16,8 +16,8 @@ readonly buffer Lights_block_1 {
 } _group_0_binding_1;
 uniform highp sampler2DArrayShadow _group_0_binding_2;
 
-smooth layout(location = 0) in vec3 _vs2fs_location0;
-smooth layout(location = 1) in vec4 _vs2fs_location1;
+smooth in vec3 _vs2fs_location0;
+smooth in vec4 _vs2fs_location1;
 layout(location = 0) out vec4 _fs2p_location0;
 
 float fetch_shadow(uint light_id, vec4 homogeneous_coords) {
diff --git a/tests/out/skybox.Fragment.glsl b/tests/out/skybox.Fragment.glsl
index c8a25b448..1a8488c2a 100644
--- a/tests/out/skybox.Fragment.glsl
+++ b/tests/out/skybox.Fragment.glsl
@@ -9,7 +9,7 @@ struct VertexOutput {
 
 uniform highp samplerCube _group_0_binding_1;
 
-smooth layout(location = 0) in vec3 _vs2fs_location0;
+smooth in vec3 _vs2fs_location0;
 layout(location = 0) out vec4 _fs2p_location0;
 
 void main() {
diff --git a/tests/out/skybox.Vertex.glsl b/tests/out/skybox.Vertex.glsl
index 2d35107bc..1b7b6167c 100644
--- a/tests/out/skybox.Vertex.glsl
+++ b/tests/out/skybox.Vertex.glsl
@@ -11,7 +11,7 @@ uniform Data_block_0 {
     mat4x4 proj_inv;
     mat4x4 view;
 } _group_0_binding_0;
-smooth layout(location = 0) out vec3 _vs2fs_location0;
+smooth out vec3 _vs2fs_location0;
 
 void main() {
     uint vertex_index = uint(gl_VertexID);