This chapter critically assesses the current state of the literature on vertical stare decisis. It begins with a consideration of how stare decisis does, or does not, fit with the principal–agent framework that is often used as a starting point for theories of the relationship between high and low courts. Various approaches to testing the existence of vertical stare decisis and the factors that might condition the strength of this constraint are then addressed. While there is a good deal of evidence that is consistent with the claim that High Court precedent constrains lower court decision-making, this evidence is not as conclusive as it might first appear. There is also ambiguity regarding the precise causal mechanism at work. This chapter then considers recent scholarship focused on the potential for bottom-up influences on the operation of precedent in a judicial hierarchy.