Grounded in the theoretical frameworks of emerging adulthood and intergenerational ambivalence, parental concerns about their child’s attainment of adulthood was investigated as the focal predictor of the likelihood of monetary conflict between American parents and emerging adults. A national sample of 791 parents (51% female; 73% White) of emerging adults (18-29 years old) completed surveys. Results showed that 43% of parents experienced monetary conflict with their emerging adult, and one in five were “very concerned” that their child would not attain adulthood. Additionally, the odds of monetary conflict were 3.11 times higher when parents endorsed greater concerns about attaining adulthood (e.g., might never become fully adult). This association was the strongest beyond key demographic, parental well-being, and parent–emerging adult relationship factors. Findings help illuminate the basis of monetary conflict in emerging adulthood and indicate parents’ fears of “failure to launch” may have very real consequences, suggesting implications for financial socialization.