diff --git a/src/wren_core.c b/src/wren_core.c
index 865c550c..74f959ae 100644
--- a/src/wren_core.c
+++ b/src/wren_core.c
@@ -960,6 +960,8 @@ DEF_PRIMITIVE(num_toString)
   // different outputs (some will format it signed and some won't). To get
   // reliable output, handle that ourselves.
   if (value != value) RETURN_VAL(wrenNewString(vm, "nan", 3));
+  if (value == INFINITY) RETURN_VAL(wrenNewString(vm, "infinity", 8));
+  if (value == -INFINITY) RETURN_VAL(wrenNewString(vm, "-infinity", 9));
 
   // This is large enough to hold any double converted to a string using
   // "%.14g". Example:
diff --git a/test/number/divide.wren b/test/number/divide.wren
index eec03f66..85aef751 100644
--- a/test/number/divide.wren
+++ b/test/number/divide.wren
@@ -2,11 +2,11 @@ IO.print(8 / 2)         // expect: 4
 IO.print(12.34 / -0.4)  // expect: -30.85
 
 // Divide by zero.
-IO.print(3 / 0)         // expect: inf
-IO.print(-3 / 0)        // expect: -inf
+IO.print(3 / 0)         // expect: infinity
+IO.print(-3 / 0)        // expect: -infinity
 IO.print(0 / 0)         // expect: nan
 IO.print(-0 / 0)        // expect: nan
-IO.print(3 / -0)        // expect: -inf
-IO.print(-3 / -0)       // expect: inf
+IO.print(3 / -0)        // expect: -infinity
+IO.print(-3 / -0)       // expect: infinity
 IO.print(0 / -0)        // expect: nan
 IO.print(-0 / -0)       // expect: nan