The Spanish Republican Navy was the naval arm of the Armed Forces of the Second Spanish Republic, the legally established government of Spain between 1931 and 1939.

The Spanish coup of July 1936 was a nationalist and military uprising that was intended to overthrow the Spanish Second Republic but precipitated the Spanish Civil War; Nationalists fought against Republicans for control of Spain. The coup was organized for 18 July 1936, although it started the previous day in Spanish Morocco, and resulted in a split of the Spanish military and territorial control, rather than a prompt transfer of power. The resulting war, Western neutrality, and active Axis support ultimately led to the establishment of a nationalist regime under Francisco Franco, who became ruler of Spain as caudillo.