• Monarch: Alfonso XIII
• President of the Council of Ministers:^[1]
  • until 19 April: Álvaro Figueroa Torres
  • 19 April – 11 June: Manuel García Prieto
  • 11 June – 3 November: Eduardo Dato Iradier
  • starting 3 November: Manuel García Prieto

• 18 January – "Manifiesto de la Liga Antigermanófila" ('Manifesto of the Anti-Germanophile League') published in La España.^[2]
• 25 June – the Juntas de Defensa [es] made their manifesto public.^[3]
• 13 August – Beginning of the 1917 general strike.^[4]
• 11 November 1917 – Municipal elections.^[5]

Undated edit

• Spanish crisis of 1917

• 23 January – Encarna Hernández, basketball player and coach (died 2022).
• 1 February – José Luis Sampedro, economist and human rights activist (died 2013).
• 20 April – María Silva Cruz, "La Libertaria", anarchist known for the 1933 Casas Viejas uprising (died 1936).
• 21 April – María Isbert, actress (died 2011).
• 1 July – Álvaro Domecq y Díez, aristocrat (died 2005)
• 4 July – Manolete, bullfighter (died 1947).
• 6 July – Heribert Barrera, Catalan nationalist politician (died 2011).
• 28 July – Gloria Fuertes, writer of children's literature (died 1998).
• 20 September – Fernando Rey, film, tv and theatre actor (died 1994).
• 25 December – Alejandro Rodríguez de Valcárcel, falangist politician, acting head of state in November 1975 (died 1976).

• 21 February – Joaquín Dicenta, journalist, novelist, playwright, poet and Republican politician (born 1862).
• 1 August – Enric Prat de la Riba, Catalan nationalist, lawyer and writer (born 1870).
• 18 August – Ricardo de Madrazo, painter best known for his Orientalist works (born 1852).
• 15 December – Gumersindo de Azcárate, Krausist educator, philosopher and Republican politician (born 1840).
• 22 December – Pío Gullón e Iglesias, lawyer, journalist and politician (born 1835).