A leash booster adapter is descripted which is attach to each end of a section of pet leash, and comprises an elastic member between shorter than the pet leash section to which it attached. In use, the device applies progressive resistance to the pet proportional to the stretching force provided by the pet pulling on the leash: the harder the pet pulls, the more resistance is felt. Rather that a hard jerk felt by the pet when it pulls, a gentle resistance is first felt, increasing in force as the pet pulls harder.
