diff --git a/src/glsl/glsl_parser.yy b/src/glsl/glsl_parser.yy
index b9897498ff7..4c871633f0e 100644
--- a/src/glsl/glsl_parser.yy
+++ b/src/glsl/glsl_parser.yy
@@ -376,6 +376,14 @@ external_declaration_list:
       if ($2 != NULL)
          state->translation_unit.push_tail(& $2->link);
    }
+   | external_declaration_list extension_statement {
+      if (!state->allow_extension_directive_midshader) {
+         _mesa_glsl_error(& @2, state,
+                          "#extension directive is not allowed "
+                          "in the middle of a shader");
+         YYERROR;
+      }
+   }
    ;
 
 variable_identifier:
diff --git a/src/glsl/glsl_parser_extras.cpp b/src/glsl/glsl_parser_extras.cpp
index b327c2b4319..890123ad1cf 100644
--- a/src/glsl/glsl_parser_extras.cpp
+++ b/src/glsl/glsl_parser_extras.cpp
@@ -210,6 +210,8 @@ _mesa_glsl_parse_state::_mesa_glsl_parse_state(struct gl_context *_ctx,
    this->early_fragment_tests = false;
    memset(this->atomic_counter_offsets, 0,
           sizeof(this->atomic_counter_offsets));
+   this->allow_extension_directive_midshader =
+      ctx->Const.AllowGLSLExtensionDirectiveMidShader;
 }
 
 /**
diff --git a/src/glsl/glsl_parser_extras.h b/src/glsl/glsl_parser_extras.h
index 6df41d442de..ce66e2fa45b 100644
--- a/src/glsl/glsl_parser_extras.h
+++ b/src/glsl/glsl_parser_extras.h
@@ -493,6 +493,8 @@ struct _mesa_glsl_parse_state {
 
    /** Atomic counter offsets by binding */
    unsigned atomic_counter_offsets[MAX_COMBINED_ATOMIC_BUFFERS];
+
+   bool allow_extension_directive_midshader;
 };
 
 # define YYLLOC_DEFAULT(Current, Rhs, N)			\
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index b699021adbd..91d9172f9c1 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -3362,6 +3362,11 @@ struct gl_constants
     */
    GLuint ForceGLSLVersion;
 
+   /**
+    * Allow GLSL #extension directives in the middle of shaders.
+    */
+   GLboolean AllowGLSLExtensionDirectiveMidShader;
+
    /**
     * Does the driver support real 32-bit integers?  (Otherwise, integers are
     * simulated via floats.)