Castillo is a Spanish surname meaning 'castle'.
The Portuguese version of this surname is Castilho.
Notable people with the surname include: As of 2014, 24.8% of all known bearers of the surname Castillo were residents of Mexico (frequency 1:191), 9.4% Venezuela (1:122), 8.1% of the Philippines (1:479), 7.6% of the United States (1:1,813), 7.3% of Colombia (1:249), 6.6% of Peru (1:184), 4.1% of Chile (1:164), 4.1% of the Dominican Republic (1:98), 4.0% of Argentina (1:413), 3.6% of Guatemala (1:172), 3.4% of Spain (1:530), 2.8% of Cuba (1:158), 2.5% of Panama (1:61), 2.3% of Ecuador (1:267), 2.2% of Honduras (1:152), 2.1% of Nicaragua (1:109), 1.3% of El Salvador (1:180) and 1.2% of Costa Rica (1:152).
In Spain, the frequency of the surname was higher than national average (1:530) in the following autonomous communities: In Panama, the frequency of the surname was higher than national average (1:61) in the following provinces: In the United States, the frequency of Castillo was higher than national average (1:1,813) in the following states:[1]