diff --git a/atom/app/command_line_args.cc b/atom/app/command_line_args.cc
index d7426de7dc56..e83eed46f2e1 100644
--- a/atom/app/command_line_args.cc
+++ b/atom/app/command_line_args.cc
@@ -1390,7 +1390,8 @@ bool IsBlacklistedArg(const base::CommandLine::CharType* arg) {
 
   if (prefix_length > 0) {
     a += prefix_length;
-    std::string switch_name(a, strcspn(a, "="));
+    std::string switch_name =
+        base::ToLowerASCII(base::StringPiece(a, strcspn(a, "=")));
     auto* iter = std::lower_bound(std::begin(kBlacklist), std::end(kBlacklist),
                                   switch_name);
     if (iter != std::end(kBlacklist) && switch_name == *iter) {