Objectives: This study sought to examine sex and ethnicity/race differences in the associations between self-esteem, weight status, and trying to lose weight among young adults in the United States. Methods: Data were drawn from Wave III (2001/2002) of the US National Longitudinal Study of Adolescent to Adult Health (Add Health public-use sample). Body mass index (BMI) was measured during in-home visits. Weight-loss patterns, self-esteem, and sociodemographics were assessed via self-reports. Logistic regression models were fitted among 4,594 young adults who were aged 21.8 (SD=1.8) years. Results: Obesity was associated with relatively poor self-esteem among both African American (P = .007) and White females (P<.006). In comparison to not trying to lose weight, trying to lose weight was associated with poorer self-esteem among normal-weight (OR = 1.23, 95% CI = 1.03-1.47) and overweight (OR=1.36, 95% CI = 1.07-1.72) White females, but not among White females with obesity (OR=1.19, 95% CI = .92-1.55), African American females (OR = .81, 95% CI = .57-1.17), or males (OR=1.00, 95% CI = .88-1.14). Conclusion: The decision to lose weight was linked with poor self-esteem solely among normal-weight and overweight. White females. African American and White females with obesity presented with relatively poor self-esteem, but their decision to lose weight was not linked with their self-esteem. More studies are needed to understand the psychological mechanism behind the decision to lose weight among White females with obesity, African American females, and males.