Rent control describes legal mechanisms that limit the amount of rent a landlord may charge or the rate at which rent can be increased during a residential (or occasionally commercial) tenancy. It is a descriptive term rather than a single defined concept and may encompass rent caps, index‑linked increases, rent review regulation and enhanced security of tenure.In England and Wales, there is no general rent control for new private sector tenancies, but historic regimes under the Rent Acts 1915–1977 and current provisions on “fair rents” for regulated tenancies still apply to a shrinking category of lettings. Assured and assured shorthold tenancies are subject instead to market‑based rents with limited statutory controls and tribunal review mechanisms.In Scotland, Ireland and Northern Ireland, modern rent control is more developed, commonly via Rent Pressure Zones or similar schemes, rent increase restrictions and tenancy tribunals or boards empowered to determine lawful rent levels.Practitioners encounter rent control issues in advising on historic tenancies, challenges to rent increases, compatibility with Article 1 Protocol 1 ECHR, investment valuation, housing policy and legislative reform affecting private rented sector regulation.