Galatea (gal'-a-tee'-a, Greek Γαλατεία) is the fourth known moon of Neptune, named after Galatea, one of the Nereids of Greek legend.

Galatea was discovered in July, 1989 from the images taken by the Voyager 2 probe. It was given the temporary designation S/1989 N 4. It is also designated Neptune VI.

It 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 Neptune.

• Orbital radius: 61,593 km
• Radius: 102 x 92 x 72 km
• Mass: 3.7×10¹⁸ kg
• Estimated density: 1.3 g/cm³
• Orbital period: 0.429 d
• Orbital inclination: 0.062°

Not to be confused with the asteroid 74 Galatea.