Plant miRNAs are short non-coding RNAs that mediate the repression of hundreds of genes. The basic plant body plan is established during early embryogenesis, and recent results have demonstrated that miRNAs play pivotal roles during both embryonic pattern formation and developmental timing. Multiple miRNAs appear to specifically repress transcription factor families during early embryogenesis. Therefore miRNAs probably have a large influence on the gene regulatory networks that contribute to the earliest cellular differentiation events in plants.