This paper is concerned with theoretical estimates of wide‐angle radiation in pencil beam antennas. In reflector‐type antennas this energy consists of direct radiation from the feed and scattered energy from the reflector. Approximate methods for the evaluation of these contributions are discussed, together with their simplifying assumptions. To get some numerical indications, calculations were made for paraboloidal reflectors of differentf/Dratios and a class of primary patterns which provide an approximate representation of a great many common feeds. The results are presented in graphical form to provide useful design information. They show the dependence of the wide‐angle radiation level on feed and dish parameters.