While burden in cancer caregivers is high and associated with poor outcomes, little is known about significance of specific supportive care needs’ domains in determining survivors’ or caregivers’ perceived caregiver burden. This cross-sectional study explored which domains of survivor- and caregiver-reported supportive care needs were most associated with survivor- and caregiver-reported caregiver burden, in breast cancer survivor–caregiver dyads. Cancer survivors (N = 55) and their caregivers (N = 44) completed measures of supportive care needs, anxiety, depression, functional well-being and perceived caregiver burden. Correlation and linear regression analyses were used to determine relative significance of survivor and caregiver supportive care needs in accounting for variance in survivor and caregiver perceptions of burden. Higher survivor-perceived caregiver burden and higher caregiver-perceived difficulty of caregiving were associated with higher levels of survivor and caregiver supportive care needs. Survivors’ psychological needs uniquely contributed to survivors’ self-perceived burden, and survivors’ sexual needs and caregivers’ work and social needs uniquely contributed to caregivers’ perceived difficulty of caregiving. Caregiver's perceived time spent caregiving was associated with access to services needs but not other needs. Survivor and caregiver supportive care needs and burden appear interdependent. Longitudinal research with larger samples is warranted to examine these relationships.