Magnetic reconnection is thought to play an important role in liberating free energy stored in stressed magnetic fields. The consequences vary from undetectable ‘nanoflares’ through jets to huge flares, which have signatures over a wide wavelength range, depending on e.g. magnetic topology, free energy content, volume, and magnetic flux density of the structures involved. Events of small energy release, which are thought to be the most numerous, are one of the key factors in the existence of a hot corona in the Sun and solar-like stars. Jets indicate magnetic reconnection between topologically different (locally closed and far-reaching, ‘open’) field lines. The majority of large flares are ejective, i.e. involve the expulsion of large quantities of mass and magnetic field from the star. Since magnetic reconnection requires small length-scales, which are well below the spatial resolution limits of even the solar observations, we cannot directly observe magnetic reconnection happening. However, there is a plethora of indirect evidences from X-rays to radio observations of magnetic reconnection. I will discuss both key observational signatures and state of the art models emphasizing synergy between observations and theory.