diff --git a/builtin.c b/builtin.c
index f184ff7f..3d726854 100644
--- a/builtin.c
+++ b/builtin.c
@@ -120,6 +120,11 @@ static void f_equal(jv input[], jv output[]) {
   output[0] = jv_bool(jv_equal(input[2], input[1]));
 }
 
+static void f_notequal(jv input[], jv output[]) {
+  jv_free(input[0]);
+  output[0] = jv_bool(jv_equal(input[2], input[1]) == 0);
+}
+
 static void order_cmp(jv input[], jv output[], int op) {
   jv_free(input[0]);
   jv a = input[2];
@@ -284,6 +289,7 @@ static struct cfunction function_list[] = {
   {f_tostring, "tostring", CALL_BUILTIN_1_1},
   {f_keys, "keys", CALL_BUILTIN_1_1},
   {f_equal, "_equal", CALL_BUILTIN_3_1},
+  {f_notequal, "_notequal", CALL_BUILTIN_3_1},
   {f_less, "_less", CALL_BUILTIN_3_1},
   {f_greater, "_greater", CALL_BUILTIN_3_1},
   {f_lesseq, "_lesseq", CALL_BUILTIN_3_1},
diff --git a/lexer.l b/lexer.l
index cac08ec7..5c6b62f4 100644
--- a/lexer.l
+++ b/lexer.l
@@ -33,6 +33,7 @@
 
 "#"[^\r\n]* { /* comments */ }
 
+"!=" { return NEQ; }
 "==" { return EQ; }
 "as" { return AS; }
 "def" { return DEF; }
diff --git a/parser.y b/parser.y
index 38e72ee3..b0e4e521 100644
--- a/parser.y
+++ b/parser.y
@@ -46,6 +46,7 @@ typedef void* yyscan_t;
 %token <literal> IDENT
 %token <literal> LITERAL
 %token EQ "=="
+%token NEQ "!="
 %token DEFINEDOR "//"
 %token AS "as"
 %token DEF "def"
@@ -79,7 +80,7 @@ typedef void* yyscan_t;
 %nonassoc '=' SETPIPE SETPLUS SETMINUS SETMULT SETDIV SETDEFINEDOR
 %left OR
 %left AND
-%nonassoc EQ '<' '>' LESSEQ GREATEREQ
+%nonassoc NEQ EQ '<' '>' LESSEQ GREATEREQ
 %left '+' '-'
 %left '*' '/'
 
@@ -142,6 +143,7 @@ static block gen_binop(block a, block b, int op) {
   case '*': funcname = "_multiply"; break;
   case '/': funcname = "_divide"; break;
   case EQ: funcname = "_equal"; break;
+  case NEQ: funcname = "_notequal"; break;
   case '<': funcname = "_less"; break;
   case '>': funcname = "_greater"; break;
   case LESSEQ: funcname = "_lesseq"; break;
@@ -282,6 +284,10 @@ Exp "==" Exp {
   $$ = gen_binop($1, $3, EQ);
 } |
 
+Exp "!=" Exp {
+  $$ = gen_binop($1, $3, NEQ);
+} |
+
 Exp '<' Exp {
   $$ = gen_binop($1, $3, '<');
 } |