Valentine Abt (born Pittsburgh June 13, 1873 – died Mayview, Pennsylvania July 16, 1942) was an American composer who specialized in the mandolin. In the book Popular American Composers, Frank L. Boyden named Abt one of America's most "prominent specialists of the mandolin", saying that he should be appreciated in Europe as well as America as "one of the greatest artists of any instrument."

Abt was a proponent of the duo-style of mandolin playing, in which one players plays back and forth between melody, counter-melody and harmony so quickly that it sounds as if two instruments are playing. Boyden credited Abt with founding a musical movement around the duo-style, as well as "trio" and "quartet" styles (that sound like three and four different instruments at once). The golden age of the mandolin around the turn of the 20th-Century included other prominent mandolin players using the style, including Samuel Siegel, W. Eugene Page, and Seth Weeks.