A 'big dog on short legs,' the Glen of Imaal Terrier is an achondroplastic dwarf breed. It is more substantial than might be expected from photographs; a typical adult Glen weighs about 36 pounds and stands 14' tall at the withers. The AKC breed standard specifies a height of 12' to 14' and a weight of 'approximately' 35 pounds for males and 'somewhat less' for females, with a length-to-height ratio of 5:3. Many champion Glens are larger than breed standard, with some individuals exceeding 40 or even 45 pounds. With three growth stages, a Glen can take up to four years to reach full maturity.