diff --git a/src/builtins.c b/src/builtins.c
index 7c4d9c6..5303659 100644
--- a/src/builtins.c
+++ b/src/builtins.c
@@ -616,6 +616,31 @@ KRK_FUNC(isinstance,{
 	}
 })
 
+static int _isSubClass(KrkClass * cls, KrkClass * base) {
+	while (cls) {
+		if (cls == base) return 1;
+		cls = cls->base;
+	}
+	return 0;
+}
+
+KRK_FUNC(issubclass,{
+	FUNCTION_TAKES_EXACTLY(2);
+	CHECK_ARG(0,class,KrkClass*,cls);
+	if (IS_CLASS(argv[1])) {
+		return BOOLEAN_VAL(_isSubClass(cls, AS_CLASS(argv[1])));
+	} else if (IS_TUPLE(argv[1])) {
+		for (size_t i = 0; i < AS_TUPLE(argv[1])->values.count; ++i) {
+			if (IS_CLASS(AS_TUPLE(argv[1])->values.values[i]) && _isSubClass(cls, AS_CLASS(AS_TUPLE(argv[1])->values.values[i]))) {
+				return BOOLEAN_VAL(1);
+			}
+		}
+		return BOOLEAN_VAL(0);
+	} else {
+		return TYPE_ERROR(class or tuple,argv[1]);
+	}
+})
+
 static KrkValue _module_repr(int argc, KrkValue argv[], int hasKw) {
 	KrkInstance * self = AS_INSTANCE(argv[0]);
 
@@ -969,6 +994,11 @@ void _createAndBind_builtins(void) {
 		"@arguments inst, cls\n\n"
 		"Determine if an object @p inst is an instance of the given class @p cls or one if its subclasses. "
 		"@p cls may be a single class or a tuple of classes.");
+	BUILTIN_FUNCTION("issubclass", FUNC_NAME(krk,issubclass),
+		"@brief Check if a class is a subclass of a type.\n"
+		"@arguments cls, clsinfo\n\n"
+		"Determine if the class @p cls is a subclass of the class @p clsinfo. @p clsinfo may be a single "
+		"class or a tuple of classes.");
 	BUILTIN_FUNCTION("globals", FUNC_NAME(krk,globals),
 		"@brief Update and a return a mapping of names in the global namespace.\n\n"
 		"Produces a dict mapping all of the names of the current globals namespace to their values. "
diff --git a/src/kuroko/util.h b/src/kuroko/util.h
index 4d235fe..ad22d38 100644
--- a/src/kuroko/util.h
+++ b/src/kuroko/util.h
@@ -206,6 +206,9 @@ static inline KrkValue discardStringBuilder(struct StringBuilder * sb) {
 #define IS_bytes(o)    IS_BYTES(o)
 #define AS_bytes(o)    AS_BYTES(o)
 
+#define IS_class(o)    IS_CLASS(o)
+#define AS_class(o)    AS_CLASS(o)
+
 #define IS_listiterator(o) krk_isInstanceOf(o,vm.baseClasses->listiteratorClass)
 #define AS_listiterator(o) AS_INSTANCE(o)
 
diff --git a/src/vendor/rline.c b/src/vendor/rline.c
index 1f3e252..00f362c 100644
--- a/src/vendor/rline.c
+++ b/src/vendor/rline.c
@@ -573,6 +573,7 @@ char * syn_krk_types[] = {
 	"print","set","any","all","bool","ord","chr","hex","oct","filter",
 	"sorted","bytes","getattr","sum","min","max","id","hash","map","bin",
 	"enumerate","zip","setattr","property","staticmethod","classmethod",
+	"issubclass",
 	NULL
 };