NGC 3945 is a barred lenticular galaxy in the constellation Ursa Major.

[5] NGC 3945 has a complex structure, with two concentric bars and a pseudobulge.

[3] Unlike classical bulges which are like miniature elliptical galaxies, pseudobulges have features similar to disk galaxies, including a flattened structure and significant rotation.

[3] The formation history of NGC 3945 is likely quite complex, with the pseudo-bulge being formed gradually from disk material, while bulges (spheroidal components) would have formed from violent merger events.

[3] Unlike galaxies with similar velocity dispersions and luminosities, the central black hole of NGC 3945 has an unusually low mass, estimated to be around 9×106 M☉.