diff --git a/doc/site/core/num.markdown b/doc/site/core/num.markdown
index a3f93bc5..42d0b415 100644
--- a/doc/site/core/num.markdown
+++ b/doc/site/core/num.markdown
@@ -42,6 +42,10 @@ The sine of the number.
 
 The square root of the number. Returns `nan` if the number is negative.
 
+### **tan**
+
+The tangent of the number.
+
 ### **-** operator
 
 Negates the number.
diff --git a/src/vm/wren_core.c b/src/vm/wren_core.c
index 32b9e23b..b5ee383b 100644
--- a/src/vm/wren_core.c
+++ b/src/vm/wren_core.c
@@ -962,6 +962,11 @@ DEF_PRIMITIVE(num_sqrt)
   RETURN_NUM(sqrt(AS_NUM(args[0])));
 }
 
+DEF_PRIMITIVE(num_tan)
+{
+  RETURN_NUM(tan(AS_NUM(args[0])));
+}
+
 DEF_PRIMITIVE(num_toString)
 {
   double value = AS_NUM(args[0]);
@@ -1594,6 +1599,7 @@ void wrenInitializeCore(WrenVM* vm)
   PRIMITIVE(vm->numClass, "sign", num_sign);
   PRIMITIVE(vm->numClass, "sin", num_sin);
   PRIMITIVE(vm->numClass, "sqrt", num_sqrt);
+  PRIMITIVE(vm->numClass, "tan", num_tan);
   PRIMITIVE(vm->numClass, "toString", num_toString);
   PRIMITIVE(vm->numClass, "truncate", num_truncate);