  Gamma-Ray Bursts (GRBs) are the strongest explosions in the Universe, which
due to their extreme character likely involve some of the strongest magnetic
fields in nature. This review discusses the possible roles of magnetic fields
in GRBs, from their central engines, through the launching, acceleration and
collimation of their ultra-relativistic jets, to the dissipation and particle
acceleration that power their $\gamma$-ray emission, and the powerful blast
wave they drive into the surrounding medium that generates their long-lived
afterglow emission. An emphasis is put on particular areas in which there have
been interesting developments in recent years.
