Clustered regularly interspaced short palindromic repeats (CRISPR)–Cpf1 has emerged as an effective genome editing tool in animals. Here we compare the activity of Cpf1 from Acidaminococcus sp. BV3L6 (As) and Lachnospiraceae bacterium ND2006 (Lb) in plants, using a dual RNA polymerase II promoter expression system. LbCpf1 generated biallelic mutations at nearly 100% efficiency at four independent sites in rice T0 transgenic plants. Moreover, we repurposed AsCpf1 and LbCpf1 for efficient transcriptional repression in Arabidopsis, and demonstrated a more than tenfold reduction in miR159b transcription. Our data suggest promising applications of CRISPR–Cpf1 for editing plant genomes and modulating the plant transcriptome.