The divide between government and opposition is clearly visible in the way members of parliament vote, but the variation in government-opposition voting has been left relatively unexplored. This is particularly the case for contextual variation in the extent to which parliamentary voting behaviour follows the government-opposition divide. This article attempts to explain levels of government-opposition voting by looking at three factors: first, the majority status of cabinets (differentiating between majority and minority cabinets), cabinet ideology (differentiating between more centrist and more extremist cabinets) and norms about cabinet formation (differentiating between wholesale and partial alternation in government). The study includes variation at the level of the country, the government and the vote. The article examines voting in the Netherlands (with a history of partial alternation) and Sweden (with a history of wholesale alternation). We find strong support for the effect of cabinet majority status, cabinet ideology and norms about cabinet formation on government-opposition voting.