The Roman conquest of Britain refers to the conquest of the island of Britain by occupying Roman forces. It began in earnest in CE 43 under Emperor Claudius, and was largely completed in the southern half of Britain by 87 when the Stanegate was established. Conquest of the far north and Scotland took longer with fluctuating success.

The Roman army was generally recruited in Italia, Hispania, and Gaul. To control the English Channel they used the newly formed fleet. The Romans under their general Aulus Plautius first forced their way inland in several battles against British tribes, including the Battle of the Medway, the Battle of the Thames, and in later years Caratacus's last battle and the Roman conquest of Anglesey. Following a widespread uprising in CE 60 in which Boudica sacked Camulodunum, Verulamium and Londinium, the Romans suppressed the rebellion in the Defeat of Boudica. They went on eventually to push as far north as central Caledonia in the Battle of Mons Graupius. Even after Hadrian's Wall was established as the border, tribes in Scotland and northern England repeatedly rebelled against Roman rule and forts continued to be maintained across northern Britain to protect against these attacks.