Events in the year 1890 in Portugal. There were 951,000 registered voters in the country.^[1]

• Monarch: Charles I
• President of the Council of Ministers: José Luciano de Castro (until 14 January), António de Serpa Pimentel (from 14 January to 14 October), João Crisóstomo de Abreu e Sousa (from 14 October)^[1]

• 11 January - British Ultimatum
• Creation of A Portuguesa, with lyrics by Henrique Lopes de Mendonça and music by Alfredo Keil.
• 30 March - Legislative election
• 14 August - Opening of Coliseu dos Recreios.
• 15 October - "Birth" of Álvaro de Campos, one of Fernando Pessoa's heteronyms.
• Establishment of the Niassa Company.

• 6 March - Francisco José Caeiro, politician (died 1956)
• 19 May - Mário de Sá-Carneiro, poet, writer (died 1916)
• 29 September - Maria Matos, actress (died 1952)
• 12 October - Luís de Freitas Branco, composer, musicologist, professor of music (died 1955)
• 20 October - Luís de Almeida Braga, writer, politician (died 1970)

• 2 April - António da Silva Porto, trader, explorer (born 1817)
• 18 April - Caetano da Costa Alegre, poet (born 1864)
• 1 June - Camilo Castelo Branco, writer (born 1825)
• 28 June - Józef Karol Konrad Chełmicki, general (born 1814 in Poland)
• 24 September - João Afonso da Costa de Sousa de Macedo, 1st Duke of Albuquerque (born 1815)
• João de Lemos, journalist, poet, dramatist (born 1819)

• List of colonial governors in 1890#Portugal