diff --git a/base/HidlSupport.cpp b/base/HidlSupport.cpp
index d657793..ef82775 100644
--- a/base/HidlSupport.cpp
+++ b/base/HidlSupport.cpp
@@ -90,6 +90,10 @@
     return *this;
 }
 
+bool hidl_string::operator< (const hidl_string &rhs) const {
+    return strcmp(mBuffer, rhs.mBuffer) < 0;
+}
+
 hidl_string::operator std::string() const {
     return std::string(mBuffer, mSize);
 }
diff --git a/base/include/hidl/HidlSupport.h b/base/include/hidl/HidlSupport.h
index 8d43bfd..e201a1e 100644
--- a/base/include/hidl/HidlSupport.h
+++ b/base/include/hidl/HidlSupport.h
@@ -154,6 +154,8 @@
     // to maintain this hidl_string alive.
     operator const char *() const;
 
+    bool operator< (const hidl_string &rhs) const;
+
     void clear();
 
     // Reference an external char array. Ownership is _not_ transferred.