ABSTRACT Typically, embryonic development is a continuous process. However, in some species, embryos can halt their development and enter a dormant state known as diapause. During this period, the embryo retains its viability and developmental capacity to resume transient embryogenesis. While the diapausing embryo appears to be in a state of suspended animation, recent studies have revealed a more dynamic picture of modulated signalling responses, metabolic rewiring and slow-paced but active tissue morphogenesis. In this Spotlight, we discuss the emerging concepts of the molecular and cellular mechanisms that govern mammalian embryonic diapause, focusing on the mouse as a model system.