diff --git a/src/main/java/net/tfminecraft/research/command/CommandManager.java b/src/main/java/net/tfminecraft/research/command/CommandManager.java
index 5ee3b1d..07ea4f7 100644
--- a/src/main/java/net/tfminecraft/research/command/CommandManager.java
+++ b/src/main/java/net/tfminecraft/research/command/CommandManager.java
@@ -2,6 +2,7 @@
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandExecutor;
@@ -43,7 +44,8 @@ public List<String> onTabComplete(CommandSender sender, Command command, String
             return Collections.emptyList();
         }
         if (args.length == 1) {
-            return SUBCOMMANDS;
+            String prefix = args[0].toLowerCase(Locale.ROOT);
+            return SUBCOMMANDS.stream().filter(sub -> sub.startsWith(prefix)).toList();
         }
         return Collections.emptyList();
     }
diff --git a/src/test/java/net/tfminecraft/research/ResearchLifecycleTest.java b/src/test/java/net/tfminecraft/research/ResearchLifecycleTest.java
index 5d7d9ae..5893581 100644
--- a/src/test/java/net/tfminecraft/research/ResearchLifecycleTest.java
+++ b/src/test/java/net/tfminecraft/research/ResearchLifecycleTest.java
@@ -131,6 +131,9 @@ class ResearchLifecycleTest {
         commands.onCommand(sender,command,"research",new String[]{"RELOAD"}); verify(sender).sendMessage("reload.success");
         commands.onCommand(sender,command,"research",new String[]{"bad"}); verify(sender).sendMessage("command.unknown_subcommand");
         assertEquals(List.of("reload"),commands.onTabComplete(sender,command,"research",new String[]{""}));
+        assertEquals(List.of("reload"),commands.onTabComplete(sender,command,"research",new String[]{"RE"}));
+        assertEquals(List.of("reload"),commands.onTabComplete(sender,command,"research",new String[]{"reload"}));
+        assertEquals(List.of(),commands.onTabComplete(sender,command,"research",new String[]{"zzz"}));
         assertEquals(List.of(),commands.onTabComplete(sender,command,"research",new String[]{"reload",""}));
     }
 }