The 6-foot-4 shooting guard chose the Eagles over N.C. State.
Langford is ranked 83rd on the ESPN 100 for 2020. He'll join his brother, Makai, who transferred after two seasons at Providence.
The versatile wing is Boston College's first marquee commitment for the 2020-21 campaign. The Eagles are also in the running for 54th-ranked prospect Andre Curbelo.