The hydraulic jump in rectangular, horizontal and non-prismatic channels is analysed. Distinction is made between the cases in which flow is non-separated and separated from the channel side-walls, respectively. Results include a rational prediction of the sequent depth ratio in terms of the inflow Froude number and the channel width ratio, the relative energy dissipation and the length characteristics of the roller and the jump. Results are presented in terms of design quantities which enables a direct and simple application in hydraulic practice.