In large-scale surveys of both children and adults, self-rated health (SRH) based on questions such as “In general, how would you rate your health?” is a widely used measurement to assess individuals’ health status. However, while a large number of studies have investigated the health aspects people consider for their responses, and some studies show deeper insights into the assessment strategies in answering this question for adults, it is largely unknown how children assess their health based on those questions. Therefore, this study examines how children rate their health according to this question in a sample of 54 9- to 12-year-olds. By using techniques of cognitive interviewing and qualitative and quantitative content analysis, we investigate the health dimensions, health factors as well as different assessment strategies that children refer to in their self-assessment of general health. Our results indicate that children in this age group mostly refer to their physical health and daily functioning or consider health more non-specifically. They also show that children take into account a wide range of specific health aspects, with some minor differences between subgroups, especially by gender. Additionally, our study highlights that children use several assessment strategies. Finally, our results indicate that the majority of children assess their health only using one health dimension, but a substantial share of children reflect on several health factors and combine different assessment strategies. We conclude that children refer to comparable health dimensions and health factors, but use somewhat different assessment strategies compared with studies focusing on adults.