| Juan B. Fernandez-Badillo | |
| Office: | Senior Judge of the United States District Court for the District of Puerto Rico |
| Term Start: | June 30, 1972 |
| Term End: | October 16, 1989 |
| Office1: | Judge of the United States District Court for the District of Puerto Rico |
| Term Start1: | October 12, 1967 |
| Term End1: | June 30, 1972 |
| Appointer1: | Lyndon B. Johnson |
| Predecessor1: | Seat established by 80 Stat. 764 |
| Successor1: | Hernan Gregorio Pesquera |
| Birth Name: | Juan B. Fernandez-Badillo |
| Birth Date: | 28 August 1912 |
| Birth Place: | Aguadilla, Puerto Rico |
| Death Place: | Guaynabo, Puerto Rico |
| Education: | University of Puerto Rico (BA, LLB) |
Juan B. Fernandez-Badillo (August 28, 1912 – October 16, 1989) was a United States district judge of the United States District Court for the District of Puerto Rico.
Born in Aguadilla, Puerto Rico, Fernandez-Badillo received a Bachelor of Arts degree from the University of Puerto Rico in 1942 and a Bachelor of Laws from the University of Puerto Rico School of Law in 1945. He entered public service in the office of the Commonwealth Attorney General of Puerto Rico, first as an assistant from 1947 to 1952, then as acting Attorney General from 1952 to 1953, then as a deputy from 1953 to 1956, and finally as the Secretary of Justice of Puerto Rico from 1957 to 1958. He was acting Governor of Puerto Rico in 1958, and was thereafter the Solicitor General of Puerto Rico from 1959 to 1967.
In 1966, the United States Congress passed an act reorganizing the United States District Court for the District of Puerto Rico as an Article III court, with the judges thereof having life tenure and salary protection. Fernandez-Badillo was nominated by President Lyndon B. Johnson on September 18, 1967, to the United States District Court for the District of Puerto Rico, to a new seat authorized by 80 Stat. 764. He was confirmed by the United States Senate on October 12, 1967, and received his commission the same day. He assumed senior status due to a certified disability on June 30, 1972. His service terminated on October 16, 1989, due to his death.