Attention deficit hyperactivity disorder (ADHD) symptoms manifest early in childhood and impact participation in daily activities and quality of life (QoL). Family routines may enhance the participation of children with ADHD. However, few studies have examined the correlations linking participation, QoL, and family routines in this population. This study aimed to describe participation patterns, environmental factors, family routines, and QoL of preschool children with ADHD, and examine the relationships of these variables. Parents of 70 children aged 4–6 (79% boys), clinically-evaluated as having ADHD or suspected ADHD, completed demographic, participation and environment, QoL and family routines measures. Frequency of participation and desire for change at home were found to be significantly higher compared to the community, while involvement did not differ between settings. Environmental factors supporting and inhibiting participation were identified. Significant correlations were found between home participation and family routines, and between home participation and QoL. The findings reinforce the need for an in-depth examination of participation patterns, environmental factors, and family routines to determine appropriate intervention goals that promote the participation and QoL of preschool children with ADHD.