The　direct　measurement　of　flexoelectric　coefficients　in　epitaxial　thin　films　is　an　unresolved　problem,　due　to　the　clamping　effect　of　substrates　which　induces　a　net　strain　(and　hence　parasitic　piezoelectricity)　in　addition　to　strain　gradients　and　flexoelectricity.　Herein,　we　propose　and　demonstrate　the　use　of　van　der　Waals　epitaxy　as　a　successful　strategy　for　measuring　the　intrinsic　(clamping-free　=　flexoelectric　coefficients　of　epitaxial　thin　films.　We　have　made,　measured,　and　compared　BaTiO3　and　SrTiO3　thin　film　capacitor　heterostructures　grown　both　by　conventional　oxide-on-oxide　epitaxy　and　by　van　der　Waals　oxide-on-mica　epitaxy,　and　found　that,　whereas　the　former　is　dominated　by　parasitic　piezoelectricity,　the　response　of　the　latter　is　truly　flexoelectric.　The　results　are　backed　by　theoretical　calculations　of　the　film-substrate　mechanical　interaction,　as　well　as　by　direct　measurements　that　confirm　the　strain-free　state　of　the　films.　van　der　Waals　epitaxy　thus　emerges　as　powerful　new　tool　in　the　study　of　flexoelectricity　and,　in　particular,　they　finally　allow　exploring　flexoelectric　phenomena　at　the　nanoscale　(where　strain　gradients　are　highest)　with　direct　experimental　knowledge　of　the　actual　flexoelectric　coefficients　of　thin　films.　©　2022　American　Physical　Society.