MicroRNAs (miRNAs) are small preserved non-coding RNA molecules that regulate gene expression post-transcriptionally by targeting the 3' UTR of mRNAs for translational repression or degradation. The rising evidence has established the significant role of miRNAs within the regulation of immune system and the prevention of autoimmunity. MiR-146a has obtained an importance as a modulator of differentiation and the function of cells of the adaptive, as well as innate immunity rapidly. In this paper, we summarize the recent understanding of the role of miR-146a in adaptive and innate immune responses, as well as in autoimmunity.