--- a/toolkit/moz.configure
+++ b/toolkit/moz.configure
@@ -593,17 +593,21 @@ option('--enable-stylo', env='STYLO_ENAB
             'This requires either building servo within Gecko\'s cargo phase '
             'or passing --with-servo')
 
 # We support setting up the appropriate options for Stylo's build-time
 # bindings generation via setting LLVM_CONFIG or by providing explicit
 # configure options.  The Windows installer of LLVM/Clang doesn't provide
 # llvm-config, so we need both methods to support all of our tier-1
 # platforms.
-llvm_config = check_prog('LLVM_CONFIG', ('llvm-config-3.9', 'llvm-config39', 'llvm-config',),
+llvm_config = check_prog('LLVM_CONFIG', ('llvm-config-4.0',
+                                         'llvm-config40',
+                                         'llvm-config-3.9',
+                                         'llvm-config39',
+                                         'llvm-config',),
                          what='llvm-config', allow_missing=True)
 
 option('--disable-stylo-build-bindgen',
        help='Enable build-time bindgen for Stylo')
 
 option('--with-libclang-path', nargs=1,
        help='Absolute path to Clang/LLVM libraries for Stylo (version 3.9.x')
 option('--with-clang-path', nargs=1,