Dogs lick their owners for a number of reasons, and each situation requires individual interpretation. In your case, the most likely explanation is that your dog is displaying an affectionate behavior that signals his close bond with you. Wild dogs often greet each other with affectionate displays of face-licking.
Other reasons put forward as to why dogs lick their owners include dominance (in a situation less intimate than cuddling) and because they enjoy the salty taste of human skin. Pups lick their mother’s mouth to persuade her to regurgitate food, and females lick their pups’ nether regions to stimulate them to eliminate—but it is unlikely that dogs lick humans for anything approaching either of these reasons. (Thankfully! Gross!)
Just be appreciative that your dog seems to enjoy your company and expresses his affection in this species-typical way. He obviously both respects you and loves you. Enjoy the moments.
Originally published in AKC Family Dog.