  We review the production of gravitational waves by an electroweak first order
phase transition. The resulting signal is a good candidate for detection at
next-generation gravitational wave detectors, such as LISA. Detection of such a
source of gravitational waves could yield information about physics beyond the
Standard Model that is complementary to that accessible to current and
near-future collider experiments. We summarise efforts to simulate and model
the phase transition and the resulting production of gravitational waves.
