diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -1509,9 +1509,17 @@
   searchPaths.emplace_back("");
   for (auto *arg : args.filtered(OPT_libpath))
     searchPaths.push_back(arg->getValue());
-  detectWinSysRoot(args);
-  if (!args.hasArg(OPT_lldignoreenv) && !args.hasArg(OPT_winsysroot))
-    addLibSearchPaths();
+  if (!config->mingw) {
+    // Don't automatically deduce the lib path from the environment or MSVC
+    // installations when operating in mingw mode. (This also makes LLD ignore
+    // winsysroot and vctoolsdir arguments.)
+    detectWinSysRoot(args);
+    if (!args.hasArg(OPT_lldignoreenv) && !args.hasArg(OPT_winsysroot))
+      addLibSearchPaths();
+  } else {
+    if (args.hasArg(OPT_vctoolsdir, OPT_winsysroot))
+      warn("ignoring /vctoolsdir or /winsysroot flags in MinGW mode");
+  }
 
   // Handle /ignore
   for (auto *arg : args.filtered(OPT_ignore)) {
diff --git a/lld/test/COFF/winsysroot.test b/lld/test/COFF/winsysroot.test
--- a/lld/test/COFF/winsysroot.test
+++ b/lld/test/COFF/winsysroot.test
@@ -13,5 +13,12 @@
 # RUN:          /defaultlib:std64 /entry:main
 
 Check that when /winsysroot is specified, %LIB% is ignored.
-# RUN: env LIB=foo.dir/sysroot/VC/Tools/MSVC/1.1.1.1/lib/x86 not lld-link %t.obj /winsysroot:%t.dir/doesnotexist /defaultlib:std32 2>&1 | FileCheck -check-prefix=LIBIGNORED %s
+# RUN: env LIB=%t.dir/sysroot/VC/Tools/MSVC/1.1.1.1/lib/x86 not lld-link %t.obj /winsysroot:%t.dir/doesnotexist /defaultlib:std32 2>&1 | FileCheck -check-prefix=LIBIGNORED %s
 LIBIGNORED: could not open 'std32.lib'
+
+Check that when -lldmingw is specified, %LIB% is ignored.
+# RUN: env LIB=%t.dir/sysroot/VC/Tools/MSVC/1.1.1.1/lib/x86 not lld-link -lldmingw %t.obj /defaultlib:std32 2>&1 | FileCheck -check-prefix=LIBIGNORED_MINGW %s
+LIBIGNORED_MINGW: could not open 'libstd32.a'
+
+# RUN: not lld-link -lldmingw %t.obj /defaultlib:std32 /winsysroot:%t.dir/sysroot 2>&1 | FileCheck -check-prefix=IGNORED_ARG %s
+IGNORED_ARG: warning: ignoring /vctoolsdir or /winsysroot flags in MinGW mode