Abstract: The laws of thermodynamics are physics’ most solid pillar, governing everything from black holes to the evolution of life. Rapid breakthroughs in optomechanics are now presenting us with the opportunity to test these laws in a completely new realm, where fluctuations are important and quantum effects might arise. I will show you how we can explore thermodynamics in this limit by probing the displacement of a nanomechanical resonator. I will discuss the potential of optomechanical systems to pave the way for experiments on quantum information thermodynamics, in particular, for revealing the thermodynamic costs of quantum operations.