Background and Aims: Parental mental health has been identified as a risk factor for adolescent gaming disorder (GD). However, the association of parents? affective states and emotion regulation with adolescents? gaming behaviors and susceptibility to problematic gaming remains underexplored. This pilot study examined the associations between parents? daily affect intensity and fluctuations and their adolescent children?s time spent gaming, using a dyadic ecological momentary assessment (EMA) approach. The study also investigated the relationship of parental emotion regulation with adolescents? risk of GD and explored factors influencing compliance with EMA. Methods: Data were collected from 64 parent-child dyads in Hong Kong through a pre-EMA survey, a 14-day EMA, and a post-EMA survey. Results: The pre- and post-EMA data revealed that adolescents were at higher risk of developing GD when their parents reported greater difficulties with emotion regulation. The EMA data revealed that adolescents spent more time gaming when their parents experienced greater intensity and fluctuations in their daily negative affect but not positive affect. The study achieved an average compliance rate exceeding 85% among parents and adolescents. Parent-child dyads were more likely to respond to EMA prompts when they were physically together or when they completed the prompts at the same time. In contrast, negative affect was associated with lower compliance rates. Discussion and Conclusions: This study provides preliminary evidence on the association between parents? emotional states and adolescents? gaming duration in parent-child dyads? daily contexts and offers findings that support the feasibility of using EMA in family and GD research.  Kulcsszavak: ecological momentary assessment, parent-child dyad, gaming disorder, parental affect, emotion regulation