Giovanni Lonfernini (born 1976) was captain regent of San Marino for the semester from October 2003 to March 2004. He is of the San Marinese Christian Democratic Party, and his co-captain-regent was Valeria Ciavatta.
Lonfernini was the second captain regent of this name, the previous one having served in 1934, 1937, and from October 1941 with Giuliano Gozi; see List of Captains Regent of San Marino.