The difficulty of formal amendment in constitutional democracies has given rise to an increasingly common phenomenon: quasi-constitutional amendments. These are sub-constitutional changes that do not possess the same legal status as a constitutional amendment, that are formally susceptible to statutory repeal or revision, but that may achieve constitutional status over time as a result of their subject-matter. The impetus for a quasi-constitutional amendment is an intent to circumvent onerous rules of formal amendment in order to alter the operation of a set of existing norms in the constitution. Where constitutional actors determine, correctly or not, that the current political landscape would frustrate their plans for a constitutional amendment to entrench new policy preferences, they resort instead to sub-constitutional means whose successful execution requires less or perhaps even no cross-party or inter-institutional coordination. This strategy sometimes results in significant changes that have the functional effect though not the formal result of a constitutional amendment. In this Chapter, I illustrate this phenomenon with reference to the Constitution of Canada, though I stress at the outset that we can observe this phenomenon elsewhere in the world.