diff --git a/src/common/UsernameSet.cpp b/src/common/UsernameSet.cpp
index 8e0a53af7..d39b8a3e4 100644
--- a/src/common/UsernameSet.cpp
+++ b/src/common/UsernameSet.cpp
@@ -59,7 +59,7 @@ void UsernameSet::insertPrefix(const QString &value)
 {
     auto &string = this->firstKeyForPrefix[Prefix(value)];
 
-    if (string.isNull() || value < string)
+    if (string.isNull() || value.compare(string, Qt::CaseInsensitive) < 0)
         string = value;
 }
 
diff --git a/src/common/UsernameSet.hpp b/src/common/UsernameSet.hpp
index 0d37f8851..f33d7d7e6 100644
--- a/src/common/UsernameSet.hpp
+++ b/src/common/UsernameSet.hpp
@@ -38,6 +38,13 @@ struct hash<chatterino::Prefix> {
 
 namespace chatterino {
 
+struct CaseInsensitiveLess {
+    bool operator()(const QString &lhs, const QString &rhs) const
+    {
+        return lhs.compare(rhs, Qt::CaseInsensitive) < 0;
+    }
+};
+
 class UsernameSet
 {
 public:
@@ -71,7 +78,7 @@ public:
 private:
     void insertPrefix(const QString &string);
 
-    std::set<QString> items;
+    std::set<QString, CaseInsensitiveLess> items;
     std::unordered_map<Prefix, QString> firstKeyForPrefix;
 };