Monocistronic is an adjective used in genetics which usually refers to messenger RNA and means that a single polypeptide chain will result from its translation.

Its antonym is polycistronic.

It is often stated that all eukaryote mRNAs are monocistronic, but the chloroplasts of plants for instance contain polycistronic transcripts, e.g. the psbb/psbH/petB/petD region.

Monocistronic mRNA are in some cases (e.g. viruses) translated to form a polyprotein, which is processed by proteolytic cleavage to form the mature gene products.