Maternal problematic smartphone use (PSU) may unintentionally model such behaviors in children and disrupt the quality of mother–child interactions. Therefore, it is essential to examine factors that potentially contribute to PSU, such as entertainment-related smartphone use (ENT), loneliness, and mothers’ ability to tolerate their child’s distress (i.e., distress intolerance; DI). Using data from 1062 mothers of preschool-aged children, we tested whether loneliness and DI moderated the relationship between ENT and PSU. Results showed small but statistically significant moderation effects of DI (b = 0.046, p =.007) and loneliness (b = 0.083, p =.006), indicating that ENT was more strongly linked to PSU among mothers experiencing higher levels of DI and loneliness. Findings suggest that the use of smartphones for entertainment may more easily develop into PSU in mothers with elevated risk factors, such as DI and loneliness. However, given the small effect sizes and the single-item assessment of entertainment-related smartphone use, these findings should be interpreted with caution.