Processes with three external electroweak gauge boson allow for a measurement of triple and quartic gauge couplings. They can be used to constrain anomalous gauge couplings, where new physics might predominantly couple to electroweak gauge bosons. In this paper we chose a class of such processes where we consider two photons and an additional vector boson in the final state. As additional vector boson we consider either a third photon or a W or Z boson. For the latter two cases we assume a leptonic decay of the boson. We calculate the next-to-leading order QCD and electroweak corrections to these processes with a particular emphasis on the until now unknown electroweak corrections. We find that the electroweak corrections to the total cross section are moderate in the range of a few per cent at most, but can reach several tens of per cent in regions of phase space that are particularly interesting in the context of new physics searches. In addition we investigate the difference between additive and multiplicative scheme when combining QCD and electroweak corrections and we assess the importance of photon induced contributions to these processes.