This article examines two contrasting views of Quebec block voting in federal elections. One view has it that the Quebec electorate tends to behave in a monolithic fashion; the other, put by Cairns in 1968, claims that this phenomenon is “a contrivance of the electoral system, not an autonomous social fact.” The evidence shows that block voting, namely, the degree to which an electorate mobilizes behind the largest party, is much more pronounced in Quebec than it is in other provinces, and especially when compared to that in Ontario. Quebec is also more likely than Ontario to determine which party forms the government. The tendency of the electoral system to magnify seat allocations to the largest party, however, is only marginally greater in Quebec relative to Ontario. At the same time, the composition of the Quebec “block” vote has varied considerably over time; it has not always been a distinctively francophone phenomenon. The article further challenges the assumption that the single-member plurality system is inherently inferior to proportional representation as a means of securing the protection of minorities in ethnically diverse societies.