Aim: The aim of this study was to assess the quality of life (QoL) and service use of parents who have preschool-aged children, and whether the mental-health problems of parents and their children predict these outcomes. Methods: Cross-sectional data were gathered in 2015–2016 in Uppsala County in Sweden where 3164 parents of children aged three- to five-years-old were asked to self-report their own and their children’s mental-health status and service use in the past 12 months. Data from the General Health Questionnaire were used to derive health-related quality of life (HRQoL) measures for adults. Results: Very few parents reported mental-health problems, while approximately 15% of the sample used any type of parental support and/or psychological health-care service. Families without problems used the least amount of resources. Parents’ own mental-health problems predicted usage of both psychotherapy and couples’ therapy, while child problems predicted the former but also the use of a parenting program. Parental HRQoL was predicted by mental-health problems, and all families with at least one individual experiencing problems rated their QoL lower than families without problems. Conclusions: Parental service use and HRQoL is associated not only with their own mental-health status but also with their children’s mental-health problems.