This aimed to identify more effective messaging strategies for online plastic surgery advertising. Grounded in Higgins’ Regulatory Focus Theory, the study experimentally examined the interaction effects of individuals’ regulatory motivation (promotion vs. prevention), message regulatory focus (promotion vs. prevention), and message appeal (rational vs. emotional). Using a 2×2×2 between-subjects factorial design, an online experiment was conducted with 320 participants, and advertising effectiveness—attitude toward the ad, intention to undergo plastic surgery, and intention to visit the clinic—was assessed. The results supported a regulatory fit effect: message effectiveness significantly increased when individuals’ regulatory motivation was congruent with the message’s regulatory focus. In addition, a three-way interaction among regulatory motivation, message regulatory focus, and message appeal was observed for attitude toward the ad. These findings underscore the importance of identifying audience characteristics and incorporating them into the design of plastic surgery advertising messages.