In recent years scientific interest has grown to understand the thermodynamics of nanoscale systems, where quantum fluctuations compete with classical fluctuations, and where the assumptions of standard thermodynamics, such as macroscopic ensembles, do not apply. QTD2019 will bring together experts working on topics in quantum thermodynamics theory and experiments that explore this new frontier with low temperature electronic circuits, trapped ions, cavity optomechanics, cold gases, NV centers and other platforms.