Although a toy breed, the Yorkie still retains much of its terrier ancestry in terms of personality. Individual dogs will differ, but they are generally intelligent, independent and courageous. Yorkshire Terriers are quick to determine where they fit in a household's pack. Their behavior towards outsiders will vary, they often will be inclined to bark at strangers, but some Yorkies are outgoing and friendly towards new people while others are withdrawn and aloof.
The differences in behavior in this regard are largely based on how the owner trains or conditions (and socializes) the Yorkie. A few individual Yorkshire Terriers may be timid or nervous, rather than bold, but the vast majority do seem to meet the breed standard for a confident, vigorous and self-important personality.
The Yorkshire Terrier seems oblivious of its small size. It is ever eager for adventure. This little dog is highly energetic, brave, loyal, and clever, with above average intelligence. Affectionate with its master, it can become suspicious of strangers and aggressive to strange dogs and small animals, if not properly socialized.