This comparative analysis of the judiciaries in Tanzania and Zambia, finds that neither has developed a strong accountability function vis-à-vis their government. It goes on to address why judges in the two countries rarely have restrained the government in politically significant cases, identifying three sets of factors that may explain why the judges perform as they do: the legal culture; the institutional structure; and the social legitimacy of the courts. The article concludes that there are signs in the Tanzanian judiciary of a certain willingness to hold the government accountable in politically salient cases, but that their opportunity to do so is limited, due to institutional, social and political factors restricting the flow of constitutional cases. The Zambian courts have more political cases and opportunities for fulfilling an accountability function vis-à-vis the executive, but are reluctant to assert such authority. This is attributed to the legal culture and to political pressure.