Classified as a small breed with medium energy, the Boston Terrier can be in three different weight classes. Males and females may vary but on average, the Boston should weigh between 15 to 25 pounds. Males can weigh under 15 pounds, but typically fall between 20 and 25 pounds. Females range from as low as 6 to 22 pounds. The average height is 15 to 17 inches.