AbstractThe growth of epitaxial complex oxides has been essentially limited to specific substrates that can induce epitaxial growth and stand high temperature thermal treatments. These restrictions hinder the opportunity to manipulate and integrate such materials into new artificial heterostructures including the use of polymeric and silicon substrates and study emergent phenomena for novel applications. To tackle this bottleneck, herein, a facile chemical route to prepare water‐soluble epitaxial Sr3Al2O6 thin films to be used as sacrificial layer for future free‐standing epitaxial complex oxide manipulation is described. Two solution processes are put forward based on metal nitrate and metalorganic precursors to prepare dense, homogeneous and epitaxial Sr3Al2O6 thin films that can be easily etched by milli‐Q water. Moreover, as a proof of concept, a basic heterostructure consisting of Al2O3/Sr3Al2O6 on SrTiO3 is fabricated to subsequently exfoliate the Al2O3 thin film and transfer it to a polymer substrate. This is a robust chemical and low‐cost methodology that could be adopted to prepare a wide variety of thin films to fabricate artificial heterostructures to go beyond the traditional electronic, spintronic, and energy storage and conversion devices.