Chronic health conditions such as asthma and eczema are common and are associated with significant psychosocial sequelae for children and their families. A number of parenting variables have been implicated in child health outcomes; however, there are gaps in understanding of the relationships between parenting and child adjustment in the context of chronic illness. This study examined the role that modifiable parenting factors including parenting style, self-efficacy, and adjustment play in explaining general and illness-related child behaviour and emotional problems. Parents (N = 107) of children diagnosed with asthma only (n = 22), eczema only (n = 59), or both conditions (n = 26) completed a range of parenting and child adjustment measures. The majority of the modifiable parenting factors (parents’ self-efficacy with managing their child’s internalising, asthma-related, and eczema-related behaviours; parent adjustment; and use of ineffective parenting strategies) made significant contributions to explaining variance child behaviour. Parenting variables consistently explained greater proportions of variance in general and illness-related child behaviour difficulties compared to demographic and illness factors and represent important intervention targets.