(19308) 1996 TO66 (provisional designation 1996 TO66) is a trans-Neptunian object that was discovered in 1996 by Chadwick Trujillo, David Jewitt and Jane Luu.

Until 20000 Varuna was discovered, it was the second-largest known object in the Kuiper belt, after Pluto.

Based on their common pattern of IR water-ice absorptions, neutral visible spectrum[7] and the clustering of their orbital elements, the other KBOs (24835) 1995 SM55, (55636) 2002 TX300, (120178) 2003 OP32 and (145453) 2005 RR43 all appear to be collisional fragments broken off of the dwarf planet Haumea.

0.110 and 0.125 every 2 million years, with additional variations on the order of ± 0.01 on much shorter time scales.

The resonance breaks every 2 million years when the eccentricity is highest and the orbit is closest to Neptune.