In a shallow saucepan, stir together the sugar and water. Cook over medium heat, stirring continuously, until sugar has dissolved into water and mixture is homogenous.
Remove syrup from heat and stir in vanilla extract.
Pour syrup into a glass jar with a lid and allow to cool, uncovered, to room temperature, before sealing and placing in fridge.
Serve simple syrup in cocktails, coffees, or cakes as desired.