Species and speciation have been called phenomena of sexual organisms, and many of the concepts developed with sexuals in mind. It is clear theoretically, however, that asexuals should be affected in similar ways by the diversifying processes that cause speciation in sexuals. This chapter investigates evidence for species and speciation in organisms with alternative lifestyles. Bdelloid rotifers are presented as a putative case of asexual species, before the theory and evidence for species in bacteria is discussed. Both theoretically and empirically, the notion that bacteria do not diversify into species can be dismissed. There are interesting differences from eukaryotes, including lower rates of recombination and greater frequency of gene transfer between distant relatives, but neither of these seems to prevent divergence into independently evolving species, at least at core genome regions. Experimental evolution is a useful but neglected avenue to test these ideas further.