Future　＇Internet　of　Things＇　requires　transferable　ferroelectric　thin　films　for　functional　devices　like　sensors　and　actuators.　We　report　here　the　growth　of　a　typical　ferroelectric　perovskite　compound,　BaTiO3,　on　a　graphene　monolayer　which　remains　intact　during　the　oxide　growth　process　at　high　temperatures　and　at　elevated　oxygen　pressure.　The　graphene　facilitates　the　crystallization　of　BaTiO3.　The　growth　of　BaTiO3　on　the　graphene　monolayer　is　found　to　follow　the　Volmer-Weber　mode　with　the　formation　of　three　dimensional　islands　at　the　initial　growth　stage.　Highly　(001)-oriented　BaTiO3　crystalline　films　are　fabricated　and　can　be　easily　exfoliated　using　a　metal　stressor　layer.　The　graphene　monolayer　remains　attached　to　the　exfoliated　BaTiO3　film　which　demonstrates　good　piezoelectric　properties.　These　results　not　only　demonstrate　the　possibility　to　fabricate　high　quality　crystalline　ferroelectric　films　via　a　graphene　monolayer,　but　also　open　the　pathway　to　realize　van　der　Waals　epitaxy　ferroelectric　films　which　can　be　transferred　onto　arbitrary　substrates,　particularly　onto　flexible　substrates　for　wearable　devices　applications.　This　journal　is　©　The　Royal　Society　of　Chemistry.