Possibly because the Standard Schnauzer was such a good ratter, the breed was originally classified by the AKC as a terrier, but in 1937, the breed club voted to switch to the Working Group because of the breed’s history as a working farm dog. The official change was made in 1945. 

It wasn’t the only change to the breed. The first breed club in the US formed in 1925 was originally called the Wirehaired Pinscher Club of America because that’s how the breed was known in Germany. The club represented both
Standard and Miniature Schnauzers, and not until 1933 did the club split into two separate clubs for the Standard and Miniature sized dogs.

Both the Standard and Miniature varieties were put into the Terrier Group when the AKC first recognized Wirehaired Pinschers as a breed in 1926. After a fair amount of protests and petitions, the Standard Schnauzer was moved into the working group, but the Miniature Schnauzer stayed in the terrier group with breeds unrelated to it genetically, but because some saw similarities in temperament and purpose, there it stayed.

Interestingly (and to our knowledge), the United States and Canada are the only countries where Miniature Schnauzers are classified as terriers. In most countries Miniature Schnauzers are placed in the “utility” category.

Image: “Schnauzer on Cream Chair” by Jenni Cator
Stockbridge Gallery
http://www.dogsinart.com