Usually the Lhasa Apso is larger than the Shih Tzu, but there are small Lhasas Apso and large Shih Tzu.
Color and Markings
Color and markings are very similar but solid color is usually more indicative of a Lhasa Apso.
The Lhasa Apso has a terrier head which is much different from the Shih Tzu.
The top is flatter where a Shih Tzu should have a domed head. The ear
placement is lower on the Lhasa Apso.
The eyes have a different shape, the Shih Tzu
being much rounder and should be larger and the Lhasa Apso being more almond shaped.
The nose of the
Shih Tzu should be even with the lower rim of the eyes. That is the top
of the nose. The Lhasa Apso has a more down nose and it is longer than the
Shih Tzu but in a poorly bred Shih Tzu that could be down also.
The Lhasa Apso is generally longer than the Shih Tzu.