Aims and objectives: This study aimed to compare family functioning and perceptions of support from nurses among Danish and Australian adult oncology patients and family members. Background: Family can have a strong influence on the health of individuals, providing support during a health crisis such as cancer. However, family functioning and supportive care from nurses may vary across cultures and settings. Design and methods: A descriptive, cross-sectional comparative design with patients and family members from Denmark and Australia. Participants were asked to fill in translated versions of the Iceland-Expressive Family Functioning Questionnaire (ICE-EFFQ) and Iceland-Expressive Family Perceived Support Questionnaire (ICE-FPSQ). Results: In total, 232 participants were recruited. The Danish cohort consisted of 56 patients and 54 family members. The Australian cohort consisted of 83 patients and 39 family members. Mean age was 59 years. No significant differences were found between Danish and Australian families. However, compared to patients, family members reported significantly lower overall family functioning, expressive emotions and communication, as well as less emotional support from nurses. Conclusions: Family functioning was comparable between Denmark and Australia. Family members reported less emotional support than patients. Nurses need to consider the patient and the family as a unit with complex needs that require monitoring and attention during oncology treatment. Implications for practice: Families supporting a member with cancer have significant and often unmet needs. Assessment, information-sharing and health education need to include the family. Supportive care information may be shared between Denmark and Australia and inspires the development of common guidelines for optimal family nursing practice.