109 Piscium b is a extrasolar planet, discovered on November 14, 1999. It is at least 6.38 times the mass of Jupiter, and it most likely is a gas giant. It orbits its host star, 109 Piscium every 1076 earth days.

It is estimated that the planet's effective temperature is 264 K (-9.15 °C, 15.53 °F), but it might be 10 or 20 K higher, due to internal heating.