diff --git a/src/main/java/com/annimon/ownlang/parser/Lexer.java b/src/main/java/com/annimon/ownlang/parser/Lexer.java
index ca4332a..e0ca7ab 100644
--- a/src/main/java/com/annimon/ownlang/parser/Lexer.java
+++ b/src/main/java/com/annimon/ownlang/parser/Lexer.java
@@ -5,6 +5,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 /**
  *
@@ -105,6 +106,10 @@ public final class Lexer {
         KEYWORDS.put("include", TokenType.INCLUDE);
     }
 
+    public static Set<String> getKeywords() {
+        return KEYWORDS.keySet();
+    }
+
     private final String input;
     private final int length;
     
diff --git a/src/main/java/com/annimon/ownlang/utils/Repl.java b/src/main/java/com/annimon/ownlang/utils/Repl.java
index 43d3986..551bc1e 100644
--- a/src/main/java/com/annimon/ownlang/utils/Repl.java
+++ b/src/main/java/com/annimon/ownlang/utils/Repl.java
@@ -14,6 +14,7 @@ import com.annimon.ownlang.parser.ast.BlockStatement;
 import com.annimon.ownlang.parser.ast.Statement;
 import com.annimon.ownlang.parser.visitors.PrintVisitor;
 import com.annimon.ownlang.utils.repl.JLineConsole;
+import com.annimon.ownlang.utils.repl.OwnLangCompleter;
 import com.annimon.ownlang.utils.repl.ReplConsole;
 import com.annimon.ownlang.utils.repl.SystemConsole;
 import java.io.IOException;
@@ -22,6 +23,7 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.stream.Collectors;
+import jline.console.completer.CandidateListCompletionHandler;
 
 public final class Repl {
 
@@ -91,7 +93,12 @@ public final class Repl {
 
     private static ReplConsole initReplConsole() {
         try {
-            return new JLineConsole();
+            JLineConsole jline = new JLineConsole();
+            CandidateListCompletionHandler handler = new CandidateListCompletionHandler();
+            handler.setPrintSpaceAfterFullCompletion(false);
+            jline.getConsole().setCompletionHandler(handler);
+            jline.getConsole().addCompleter(new OwnLangCompleter(HELP, VARS, FUNCS, SOURCE, RESET, EXIT));
+            return jline;
         } catch (IOException ioe) {
             return new SystemConsole();
         }
diff --git a/src/main/java/com/annimon/ownlang/utils/repl/OwnLangCompleter.java b/src/main/java/com/annimon/ownlang/utils/repl/OwnLangCompleter.java
new file mode 100644
index 0000000..e0a2f9e
--- /dev/null
+++ b/src/main/java/com/annimon/ownlang/utils/repl/OwnLangCompleter.java
@@ -0,0 +1,34 @@
+package com.annimon.ownlang.utils.repl;
+
+import com.annimon.ownlang.lib.Functions;
+import com.annimon.ownlang.lib.Variables;
+import com.annimon.ownlang.parser.Lexer;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import jline.console.completer.StringsCompleter;
+
+public final class OwnLangCompleter extends StringsCompleter {
+
+    private final Set<String> staticCandidates;
+
+    public OwnLangCompleter(String... candidates) {
+        staticCandidates = new HashSet<>();
+        Collections.addAll(staticCandidates, candidates);
+    }
+
+    @Override
+    public int complete(String buffer, int cursor, List<CharSequence> candidates) {
+        updateCandidates();
+        return super.complete(buffer, cursor, candidates);
+    }
+
+    private void updateCandidates() {
+        getStrings().clear();
+        getStrings().addAll(Lexer.getKeywords());
+        getStrings().addAll(staticCandidates);
+        getStrings().addAll(Variables.variables().keySet());
+        getStrings().addAll(Functions.getFunctions().keySet());
+    }
+}