← 1779 1778 1777 1780 in Portugal → 1781 1782 1783
Centuries:	16th 17th 18th 19th 20th
Decades:	1760s 1770s 1780s 1790s 1800s
See also:	List of years in Portugal

Events in the year 1780 in Portugal.

Incumbents

• Monarch: Mary I

Events

• 16 January – Battle of Cape St. Vincent, a naval battle off the southern coast of Portugal during the Anglo-Spanish War. A British fleet defeated a Spanish squadron.

Births

• 10 May – José Homem Correia Teles, judge and politician (d. 1849).^[1]

• 20 May – José Bernardino de Portugal e Castro, marquis (d. 1840)
• 12 July – Mouzinho da Silveira, statesman, jurist and politician (d. 1849)

Deaths

• 18 January – Gaspar of Braganza, Archbishop of Braga (b. 1714)
• 23 October – João da Bemposta (b. 1726)

Full date missing

• Abade António da Costa, composer (b. 1714)
• Miguel António do Amaral, court painter (b. 1710)