diff --git a/src/admc/gplink.cpp b/src/admc/gplink.cpp
index e1d485c7..7bfd5203 100644
--- a/src/admc/gplink.cpp
+++ b/src/admc/gplink.cpp
@@ -82,7 +82,12 @@ QList<QString> Gplink::get_gpos() const {
 
 void Gplink::add(const QString &gpo_case) {
     const QString gpo = gpo_case.toLower();
-    
+
+    const bool gpo_already_in_link = gpo_case_map.contains(gpo);
+    if (gpo_already_in_link) {
+        return;
+    }
+
     gpos_in_order.append(gpo);
     options[gpo] = 0;
     gpo_case_map[gpo] = gpo_case;
diff --git a/tests/admc_test_gplink.cpp b/tests/admc_test_gplink.cpp
index a68ed2b4..01ea3862 100644
--- a/tests/admc_test_gplink.cpp
+++ b/tests/admc_test_gplink.cpp
@@ -60,9 +60,15 @@ void ADMCTestGplink::test_add() {
     const QString gplink_string = "[LDAP://a;0][LDAP://b;0][LDAP://c;0][LDAP://UPPER;0]";
     Gplink gplink(gplink_string);
 
+    // Simple add
     gplink.add("added gpo");
+
+    // Test that case is preserved
     gplink.add("added gpo UPPERCASE");
 
+    // Test that duplicates are ignored
+    gplink.add("a");
+
     const QString correct_gplink_string = "[LDAP://a;0][LDAP://b;0][LDAP://c;0][LDAP://UPPER;0][LDAP://added gpo;0][LDAP://added gpo UPPERCASE;0]";
 
     test_gplink_equality(gplink, correct_gplink_string);