Despite the current popularity of the UK National Lottery, psychologists have tended to neglect lottery play. This review provides a summary of current research findings and outlines the main cognitive theories of gambling as related to non-pathological lottery play. A discussion of various biases and irrational thinking patterns typically found in lottery gambling will be given. These will include the misunderstanding of lottery odds, a susceptibility to the gambler's fallacy and cognitive entrapment, a belief in hot and cold numbers, unrealistic optimism, a belief in personal luck, superstitious thinking, the illusion of control, the erroneous perception of near misses, a susceptibility to prize size and rollover effects, the framing of gambling outcomes and finally, the influence of social factors on lottery play. It is concluded that the psychology of lottery play needs a more unified theory which whilst largely cognitive in emphasis, should also incorporate social motivations such as those inherent in syndicate based lottery play.