Within the Mephitidae family, the spotted skunk is most closely related to the eastern spotted skunk (*Spilogale putorius*) and the western spotted skunk (*Spilogale gracilis*).
Here's a breakdown of its relatedness:
* Family: Mephitidae (Skunks)
* Genus: *Spilogale* (Spotted skunks)
* Species: *Spilogale putorius* (Spotted skunk)
So, to answer your question, the spotted skunk is most closely related to other spotted skunks, and then more broadly to all skunks.