My object is to analyse the concept of a legal power to change a constitution (and more broadly, to change constitutional law). I will look at how the notions of constitution-making (constitution-changing) powers used in constitutional change literature map onto debates specifically on legal powers (in public law and in private law). For instance, I will look at the relationship between primary constituent power and legal powers. I will also discuss what are the conditions for a legal power to change a constitution to exist, and in particular, what sort of agent can hold it (could it be the people?) and how broad the concept of a legal power is. Within the last theme, I will ask whether we should distinguish some other category of legal capacity for constitutional change (specifically legal influence over it), without having a legal power.