American Staffordshire terriers are on the larger side for medium-size dogs, with female Am Staffs typically being slightly smaller than the males.
The Australian cattle dog is an active and intelligent dog breed that is right in the middle of the medium-size category. This compact and athletic dog is driven to work.
The Australian shepherd is a very intelligent, high-energy, medium-size dog breed. This herding breed also is quite agile and athletic and therefore well-suited to dog sports, such as flying disc and agility.
The Basenji, a medium-sized hound breed originating from Africa, is a unique canine with a fascinating set of characteristics. Known as the "barkless dog," the Basenji's voice resembles a yodel or chortle rather than the typical barking sound.
A medium-sized dog, the Portuguese water dog is an intelligent and generally friendly breed. Individuals make great service dogs and have a natural ability to swim.
The happy-go-lucky beagle is a favorite among those who want a dog that is moderately active and very friendly and sweet. Beagles fall on the small side of the medium range.
The bearded collie is a clever and outgoing dog breed. Hovering at around 50 pounds, the dog is actually smaller than it appears to be. Its fluffy coat gives it a large presence, but its frame underneath is lean and agile.
The border collie is one of the smartest dog breeds as well as a high-energy pup. This medium-size dog packs a lot of athleticism into a compact body, and it loves to work.
The Scottish Terrier, affectionately called the Scottie, may be little, but it doesn’t lack in the personality department. These feisty dogs are often recognized for their distinct head shape and beard-like facial hair.