Informal caregivers are an essential part of health and social care systems worldwide. As such, they may need professional support. The aim of this study was to describe informal caregivers' experiences and need for support from a tailored primary health care (PHC) unit. This is a qualitative descriptive study using data collected from five semi-structured focus group discussions with a purposeful sample of 16 informal caregivers of older relatives. Respondents were recruited from a tailored PHC unit for people aged 75 years or older in a region in central Sweden. The data were analysed by qualitative content analysis with an abductive approach, based on the principles of the patient- and family-centred care framework. The overarching theme was 'Striving for partnership'. The findings indicate that informal caregivers to some extent felt supported by the healthcare professionals. However, the caregivers expressed a need to be further acknowledged by the professionals in order to participate in the care of their older relatives in the way they wanted. Moreover, insufficient information regarding the older adult's health condition and care provided by the professionals had a negative impact on the caregiver's participation in care. Informal caregivers have unmet needs for support and strive for a partnership with the PHC professionals. PHC professionals should be more attentive and invite informal caregivers to participate in the care of the older adult in order to meet their support needs and build an equal partnership. The patient- and family-centred care framework may be of guidance when providing care for older adults in a PHC context.