| NGC 3972 | |
| Z: | 0.002799 |
| Group Cluster: | NGC 3992 Group |
| Type: | SA(s)bc, SBbc |
| Appmag V: | 13.14 |
NGC 3972 is a spiral galaxy located in the northern constellation of Ursa Major. It was discovered by William Herschel on April 14, 1789. This galaxy is located 66 million light years away and is receding with a heliocentric radial velocity of . It is a member of the NGC 3992 Group of galaxies.
Type Ia supernova SN 2011by was discovered in this galaxy on April 26, 2011, by Zhangwei Jin and Xing Gao in China. It was magnitude 14.2 ten days short of maximum, and positioned at an offset east and north of the galactic nucleus.