Objective This study explored the association between healthcare needs and quality of life (QoL) of Korean cancer family caregivers according to the time lapse after cancer diagnosis. Methods Self‐administered comprehensive needs assessment tool and EuroQol‐5‐dimension index for 686 cancer family caregivers were classified into four groups according to time lapse after cancer diagnosis (≤12, 13–36, 37–60,>60 months). We estimated the association between unmet needs and QoL by multiple linear regression analyses after adjusting for age, sex, cancer site and caregivers’ comorbid conditions. Results Female or elder caregivers had lower QoL and higher unmet needs. The highest unmet needs existed in healthcare staff domain followed by information/education domain persistently along all periods. QoL of caregivers was significantly associated with family/social support and health/psychological problem during the time lapse of ≤12 months as well as >60 months. Practical support was consistently associated with QoL across all time lapses. Religious/spiritual support and hospital facilities and services showed significant association with QoL only in ≤12 months and >60 months respectively. Conclusions The QoL of Korean cancer family caregivers was differentially associated with their unmet needs according to the time lapse after cancer diagnosis and by specific domains of needs.