diff --git a/vec2.lua b/vec2.lua
index f964074..9f88c5a 100644
--- a/vec2.lua
+++ b/vec2.lua
@@ -433,6 +433,20 @@ function vec2:abs()
 	return self:copy():absi()
 end
 
+-----------------------------------------------------------
+-- sign
+-----------------------------------------------------------
+
+function vec2:signi()
+	self.x = math.sign(self.x)
+	self.y = math.sign(self.y)
+	return self
+end
+
+function vec2:sign()
+	return self:copy():signi()
+end
+
 -----------------------------------------------------------
 -- truncation/rounding
 -----------------------------------------------------------