How does an embryo make its first decisions, separating top from bottom, and left from right? Embryonic development relies on a series of symmetry-breaking events that pattern tissues with a global body plan and sculpt symmetric cell collections into functional organs. Developmental biologists continue to uncover an ever-wider range of mechanisms to drive symmetry breaking, including nonlinear gene network dynamics, tissue mechanics, and embryonic fluid hydrodynamics. Increasingly, recent efforts by physicists have contributed theories built upon concepts of symmetry breaking that suggest a path toward unified principles of development. This KITP conference will bring together developmental biologists and theoretical physicists to assess the landscape of symmetry breaking processes in development and clarify the path towards a unified theory of morphogenesis.