The purpose of this study was to review a series of studies (N = 17) regarding the effects of using various methods when training dogs. The reviewed studies examined the differences between training methods (e.g., methods based on positive reinforcement, positive punishment, escape/avoidance, et cetera) on a dog's physiology, welfare, and behavior toward humans and other dogs. The reviewed studies included surveys, observational studies, and interventions. The results show that using aversive training methods (e.g., positive punishment and negative reinforcement) can jeopardize both the physical and mental health of dogs. In addition, although positive punishment can be effective, there is no evidence that it is more effective than positive reinforcement–based training. In fact, there is some evidence that the opposite is true. A few methodological concerns arose from the reviewed studies. Among them are small sample sizes, missing data on effect size, possible bias when coding behavior in observational studies, and the need to publish case reports of bodily damage caused by aversive training methods. In conclusion, those working with or handling dogs should rely on positive reinforcement methods and avoid using positive punishment and negative reinforcement as much as possible.