The Battle of Montijo was fought on 26 May 1644, in Montijo, Spain, between Portuguese and Spanish forces. Although the battle ended with a Portuguese victory, the Spanish saw it as a strategic success as they claimed to have prevented Matias de Albuquerque from capturing Badajoz, despite Albuquerque having no intention of attacking the city. Due to the chaotic nature of the battle, casualty figures vary.

The Portuguese Restoration War (Portuguese: Guerra da Restauração) was the war between Portugal and Spain that began with the Portuguese revolution of 1640 and ended with the Treaty of Lisbon in 1668, bringing a formal end to the Iberian Union. The period from 1640 to 1668 was marked by periodic skirmishes between Portugal and Spain, as well as short episodes of more serious warfare, much of it occasioned by Spanish and Portuguese entanglements with non-Iberian powers. Spain was involved in the Thirty Years' War until 1648 and the Franco-Spanish War until 1659, while Portugal was involved in the Dutch–Portuguese War until 1663.

In the seventeenth century and afterwards, this period of sporadic conflict was simply known, in Portugal and elsewhere, as the Acclamation War. The war established the House of Braganza as Portugal's new ruling dynasty, replacing the House of Habsburg who had been united with the Portuguese crown since the 1581 succession crisis.