diff --git a/Libraries/LibJS/Runtime/CommonPropertyNames.h b/Libraries/LibJS/Runtime/CommonPropertyNames.h
index c79625caee..6037687e40 100644
--- a/Libraries/LibJS/Runtime/CommonPropertyNames.h
+++ b/Libraries/LibJS/Runtime/CommonPropertyNames.h
@@ -60,11 +60,13 @@ namespace JS {
     P(Symbol)                                \
     P(UTC)                                   \
     P(abs)                                   \
+    P(acos)                                  \
     P(acosh)                                 \
     P(apply)                                 \
     P(arguments)                             \
     P(asIntN)                                \
     P(asUintN)                               \
+    P(asin)                                  \
     P(asinh)                                 \
     P(atan)                                  \
     P(atanh)                                 \
diff --git a/Libraries/LibJS/Runtime/MathObject.cpp b/Libraries/LibJS/Runtime/MathObject.cpp
index 177229a069..c4057f30ff 100644
--- a/Libraries/LibJS/Runtime/MathObject.cpp
+++ b/Libraries/LibJS/Runtime/MathObject.cpp
@@ -60,7 +60,9 @@ void MathObject::initialize(GlobalObject& global_object)
     define_native_function(vm.names.expm1, expm1, 1, attr);
     define_native_function(vm.names.sign, sign, 1, attr);
     define_native_function(vm.names.clz32, clz32, 1, attr);
+    define_native_function(vm.names.acos, acos, 1, attr);
     define_native_function(vm.names.acosh, acosh, 1, attr);
+    define_native_function(vm.names.asin, asin, 1, attr);
     define_native_function(vm.names.asinh, asinh, 1, attr);
     define_native_function(vm.names.atan, atan, 1, attr);
     define_native_function(vm.names.atanh, atanh, 1, attr);
@@ -273,6 +275,18 @@ JS_DEFINE_NATIVE_FUNCTION(MathObject::clz32)
     return Value(__builtin_clz((unsigned)number.as_double()));
 }
 
+JS_DEFINE_NATIVE_FUNCTION(MathObject::acos)
+{
+    auto number = vm.argument(0).to_number(global_object);
+    if (vm.exception())
+        return {};
+    if (number.is_nan() || number.as_double() > 1 || number.as_double() < -1)
+        return js_nan();
+    if (number.as_double() == 1)
+        return Value(0);
+    return Value(::acos(number.as_double()));
+}
+
 JS_DEFINE_NATIVE_FUNCTION(MathObject::acosh)
 {
     auto number = vm.argument(0).to_number(global_object);
@@ -283,6 +297,16 @@ JS_DEFINE_NATIVE_FUNCTION(MathObject::acosh)
     return Value(::acosh(number.as_double()));
 }
 
+JS_DEFINE_NATIVE_FUNCTION(MathObject::asin)
+{
+    auto number = vm.argument(0).to_number(global_object);
+    if (vm.exception())
+        return {};
+    if (number.is_nan() || number.is_positive_zero() || number.is_negative_zero())
+        return number;
+    return Value(::asin(number.as_double()));
+}
+
 JS_DEFINE_NATIVE_FUNCTION(MathObject::asinh)
 {
     auto number = vm.argument(0).to_number(global_object);
diff --git a/Libraries/LibJS/Runtime/MathObject.h b/Libraries/LibJS/Runtime/MathObject.h
index cf84b28344..ff5f779775 100644
--- a/Libraries/LibJS/Runtime/MathObject.h
+++ b/Libraries/LibJS/Runtime/MathObject.h
@@ -56,7 +56,9 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(expm1);
     JS_DECLARE_NATIVE_FUNCTION(sign);
     JS_DECLARE_NATIVE_FUNCTION(clz32);
+    JS_DECLARE_NATIVE_FUNCTION(acos);
     JS_DECLARE_NATIVE_FUNCTION(acosh);
+    JS_DECLARE_NATIVE_FUNCTION(asin);
     JS_DECLARE_NATIVE_FUNCTION(asinh);
     JS_DECLARE_NATIVE_FUNCTION(atan);
     JS_DECLARE_NATIVE_FUNCTION(atanh);