AbstractThis unit provides information on the replication cycle of insect baculovirus to provide an understanding of how this virus has been adapted for use as an expression vector for recombinant proteins in insect cells. We provide an overview of the virus structure and its unique bi‐phasic replication cycle, which has been exploited in developing the virus as an expression vector. We also review the development of the baculovirus expression vector system (BEVS), from the mid‐1980s to the present day in which the BEVS is now an established tool for the production of a range of recombinant proteins and multi‐protein complexes including virus‐like particles. We describe advances made to the BEVS to allow the rapid and easy production of recombinant viruses and developments to improve protein yield. We finish by describing the application of recombinant BacMam as vectors for the delivery of genes into mammalian and human cells. © 2018 by John Wiley & Sons, Inc.