Despina (des-pee'-na or des-pye'-na; Latin Despœna from Greek Δεσποίνη) is the third known moon of Neptune. It is named after Despina, a nymph who was a daughter of Poseidon.

Despina was discovered in July, 1989 from the images taken by the Voyager 2 probe. It was given the temporary designation S/1989 N 3. It is also designated Neptune V.

Despina is irregularly shaped and shows no sign of any geological modification. Since its orbit is below Neptune's synchronous orbit radius it is slowly decaying due to tidal forces and will one day break up into a planetary ring or impact on Neptune's surface.

• Orbital radius: 52,526 km
• Radius: 90 x 74 x 64 km
• Mass: 2.1×10¹⁸ kg
• Estimated density: 1.2 g/cm³
• Orbital period: 0.335 d
• Orbital inclination: 0.064°