In 1808, the 29th joined Wellington's army engaged in the 1807-1814 Peninsular War in Spain and Portugal. At Roliça on 17 August, it suffered heavy losses assaulting an entrenched French position, which was taken only after a prolonged defence; at Vimeiro four days later, it held off an attack by Brenier's Brigade, allowing two other British battalions to first regroup, then repulse the attack.