Alejo Razulo Mabanag (July 14, 1886 – after 1961) was a Filipino lawyer and politician.

[1] He then placed second in the bar examinations the same year and opened a law firm in Lingayen, Pangasinan.

[1] Upon the establishment of the Commonwealth government in 1935, President Manuel L. Quezon appointed him Judge of the Court of First Instance of Iloilo up to 1938 and later named as city fiscal of Manila until 1945.

[1] He successfully ran for an at-large seat in the Senate in 1946 but lost reelection in 1949.

[1] In 1959, he was appointed by President Carlos P. Garcia to become his Secretary of Justice before his term in the Senate ended.