The present invention provides a height-adjustment mechanism for an armrest. In an embodiment, a height-adjustment mechanism for an armrest includes an integral one-piece leverage body, and an integral one-piece sleeve. In an embodiment, the integral one-piece sleeve has pivot seats formed on a pair of locking arms depending from a first wall of the sleeve. These parts may be made of low cost materials suitable for integrally forming their features in an injection-moulding operation. Various features built into these parts may provide a user with a sense of quality.