Abstract: The study of oxide heteroepitaxy has been hindered by the issues of misfit strain and substrate clamping, which impede both the optimization of performance and the acquisition of a fundamental understanding of oxide systems. Recently, however, the development of freestanding oxide membranes has provided a plausible solution to these substrate limitations. Single-crystalline functional oxide films can be released from their substrates without incurring significant damage and can subsequently be transferred to any substrate of choice. This paper discusses recent advancements in the fabrication, adjustable physical properties, and various applications of freestanding oxide perovskite films. First, we present the primary strategies employed for the synthesis and transfer of these freestanding perovskite thin films. Second, we explore the main functionalities observed in freestanding perovskite oxide thin films, with special attention tothe tunable functionalities and physical properties of these freestanding perovskite membranes under varying strain states. Next, we encapsulate three representative devices based on freestanding oxide films. Overall, this review highlights the potential of freestanding oxide films for the study of novel functionalities and flexible electronics.