Theoretically grounded in the cognitive behavioral model of pathological internet use, we examined the association between parenting by lying and mobile phone addiction and explored the mediating effect of maladaptive cognition and the moderating effect of unconditional acceptance. In this study, maladaptive cognition refers to distorted patterns of thinking associated with internet use. A questionnaire survey was conducted on a sample of 1305 adolescents. The results suggested that parenting by lying was positively associated with mobile phone addiction, with maladaptive cognition acting as a mediator and unconditional acceptance as a moderator. The association between parenting by lying and maladaptive cognition was weaker among adolescents with high unconditional acceptance than among those with low unconditional acceptance. The results suggest that, although parenting by lying may have negative outcomes for adolescents, positive perceptions of their parents can partially reduce this negative effect.