Liver X receptors (LXRs) are members of the nuclear receptor superfamily that are activated by specific oxysterols. LXRs heterodimerize with retinoid X receptors to regulate positively the expression of a variety of target genes, many of which are involved in lipid and glucose metabolism. In the last few years, new targets of LXR activation have been identified with roles in the modulation of immune responses. Moreover, LXRs mediate repression of inflammatory pathways through mechanisms collectively known as transrepression. Here, we revise recent findings on the impact of LXR activation on immune responses, with an emphasis on advances in the understanding of the molecular mechanisms that mediate these effects.