Gary Thomas Smalley was an American family counselor, president, and founder of the Smalley Relationship Center. He was renowned for his books on family relationships from a Christian perspective. Among other topics, he taught about the four temperaments using a format based on animals: the otter, lion, golden retriever, and beaver.

Gary Smalley was one of the country's best-known authors and speakers on family relationships. He was the award-winning, best-selling author or coauthor of sixteen books, as well as several popular films and videos. The Blessing and The Two Sides of Love have won Gold Medallions, The Language of Love won the Angel Award as the best contribution to family life, and his other titles have received Silver Medallions.

His national infomercial Hidden Keys to Loving Relationships has been viewed by television audiences all over the world.