7866 Sicoli, provisional designation 1982 TK, is a stony Nysa asteroid from the inner regions of the asteroid belt, approximately 6 kilometers in diameter. It was discovered on 13 October 1982, by American astronomer Edward Bowell at Lowell's Anderson Mesa Station near Flagstaff, Arizona.^[7] The asteroid was named after Italian astronomer Piero Sicoli.^[2]

Sicoli is a member of the stony subgroup of the Nysa family, one of the smaller families in the main-belt, named after its namesake, 44 Nysa. The body orbits the Sun in the inner main-belt at a distance of 1.9–2.9 AU once every 3 years and 9 months (1,382 days). Its orbit has an eccentricity of 0.21 and an inclination of 3° with respect to the ecliptic.^[1] The first precovery was taken at Palomar Mountain in 1954, extending the asteroid's observation arc by 28 years prior to its discovery.^[7]

This minor planet was named in honor of Italian astronomer Piero Sicoli (born 1954), a discoverer of minor planets and Observation Coordinator at the Sormano Astronomical Observatory in northern Italy.^[2] The official naming citation was published by the Minor Planet Center on 28 July 1999 (M.P.C. 35488).^[8]