Objectives Describe daily sleep patterns, sleep quality, and sleep hygiene in 2–5-year-old children newly diagnosed with juvenile idiopathic arthritis (JIA) and their parents in comparison with typically developing (TD) children and parents. Methods Participants (13 JIA, 16 TD parent–child dyads) wore actigraphs for 10 days. Parents completed sleep diaries and sleep hygiene survey. Results Children with JIA had significantly less total sleep time, lower sleep efficiency (SE), and longer naps than TD children. Parents of children with JIA had significantly earlier bedtimes, more wake after sleep onset (WASO) and lower SE than TD parents. Parent–child SE and WASO were interrelated in JIA dyads. Sleep hygiene practices were inconsistent in both groups of children. Conclusions Inadequate amounts of sleep and poor sleep quality were common in parent–child dyads. Early interventions to improve sleep duration and promote sleep hygiene practices may alleviate future sleep problems and improve parent and child well-being.