Tropical Storm Zeta was the twenty-eighth and last storm of the 2005 Atlantic hurricane season. It formed very late during the year on December 30, after the official end of the season, and was a very rare tropical cyclone to live during two calendar years.

Tropical Storm Zeta formed on December 30 in the central Atlantic Ocean, where it stayed far away from land during its whole lifetime. While every forecast given to the storm predicted it to dissipate quickly, Zeta, like Hurricane Epsilon, denied those advisories. Zeta reached to its maximum strength on January 2 until finally dissipating on January 8, also bringing the close to the end of the 2005 season.