Many extensions of the Standard Model feature spontaneously broken new symmetries that give rise to bosonic particles with naturally small masses and couplings. These so-called axion-like particles (ALPs) can constitute some or all of dark matter or mediate the interactions between dark and visible matter. In my talk I will review the various ways in which ALPs can couple to Standard Model particles and discuss the resulting phenomenology. A particular focus will be on MeV-scale ALPs, which can be explored with a wide range of particle physics experiments, such as precision measurements of rare meson decays, electron-positron colliders, and fixed-target experiments. I will also present astrophysical constraints, in particular from supernovae, and possible hints for keV-scale ALPs from the XENON1T experiment.
