Determining the child’s best interests in a hospital setting will ideally involve the combined views of children, parents, and healthcare professionals. However, few studies have explored parents’ experiences of their child’s best interests when they engage with the healthcare system. Therefore, this study aimed to explore parents’ experiences of their child’s best interests during hospitalisation. A descriptive qualitative inductive design using face-to-face parent–child combined interviews, analysed by latent content analysis, was used. Sixteen parents recruited from a tertiary hospital in Western Australia were interviewed. Collaboration, development of trustworthy relationships, and effective communication were essential in shaping parents’ experiences of their child’s best interests during hospitalisation.