This chapter examines theories of parliament and parliamentarism in Victorian Britain. The first part of the chapter offers a general survey of Victorian constitutional theory. I demonstrate that while Constant’s conception of parliamentarism was defeated in France, it triumphed in Britain, where Victoria was widely viewed as a monarch who reigned but did not govern, and a range of authors argued that ministers must hold power through persuasion rather than patronage. I then consider Walter Bagehot, the most famous Victorian theorist of parliamentarism, who developed the argument that parliamentarism was intrinsically superior to the American constitutional model. Finally, I turn to John Stuart Mill. I demonstrate that Mill shared the widespread Victorian belief in parliamentarism, and I argue that his true project in Considerations on Representative Government was to discover a way to harmonize Victorian parliamentarism and electoral democracy.