D'Addario is a manufacturer of musical instrument strings and accessories, primarily for guitars but also many other fretted and orchestral instruments. The company currently has its European headquarters in Newcastle upon Tyne, Tyne and Wear, England. It is a family-owned and operated business that is one of the largest string manufacturers in the world.
D'Addario also produces and distributes other musical accessories under other brands. Some of the products offered are cables, capos, ear plugs, electronic tuners, straps, humidifiers, picks, slides, drumheads, drum sticks, and reeds for woodwind instruments.