NGC 3938 is an unbarred spiral galaxy in the Ursa Major constellation. It was discovered on 6 February 1788 by William Herschel. It is one of the brightest spiral galaxies in the Ursa Major South galaxy group, and is roughly 67,000 light years in diameter. It is approximately 43 million light yearsaway from Earth. NGC 3938 is classified as type Sc under the Hubble sequence, a loosely wound spiral galaxy with a smaller and dimmer bulge.The spiral arms of the galaxy contain many areas of ionized atomic hydrogen gas, more so towards the center.

Two supernovae have been identified within NGC 3938. SN 2005ay is a type II supernova that was discovered on 27 March 2005 and had a magnitude of 15.6. SN 2017ein is a type Ic supernova that was discovered on 25 May 2017 and peaked at magnitude 14.9.