Purpose: Our study aimed to investigate the relationship between unmet supportive care needs and carer burden and happiness, in head and neck cancer (HNC). Methods: Two hundred eighty-five HNC informal carers were sent a postal questionnaire between January and June 2014, which included the supportive care needs survey for partners and caregivers of cancer survivors (SCNS-P&C) and the CarerQol, which assesses burden and happiness. Multiple regression analysis was conducted to examine the association of (i) carer characteristics, (ii) carer situation, and (iii) unmet supportive care needs, with carer burden and happiness Results: One hundred ninety-seven carers completed the questionnaire (response rate = 69 %), 180 of whom were included in the analysis. The majority were female (76 %), not in paid employment (68 %) and caring for their spouse (67 %). On average, carers reported relatively low levels of burden and relatively high levels of happiness. Carer factors explained 42 % of variance in levels of burden and 24 % of variance in levels of happiness. Healthcare service needs were associated with carer burden (β = .28, p = .04), while psychological needs (β = −.38, p = .028), health care service needs (β = −.30, p = .049), information needs (β = .29, p = .028), carer comorbidity (β = −.18, p = .030), and gender (β = −.16, p = .045) were associated with happiness. Conclusions: Our results indicate that different aspects of carer characteristics and unmet needs are associated with carer burden and happiness. Efforts directed at reducing unmet healthcare service needs in particular are merited given their associations with both aspects of carer quality of life.