Background Women in homelessness face complex needs requiring coordinated support. Though participation is a legal right, meaningful involvement is challenging. Greater insight is needed to strengthen intersectoral collaboration and support their participation. Objectives The aim was to investigate perceptions of the conditions, barriers, and enablers of intersectoral collaboration in providing care, support, and opportunities for participation for women in homelessness from the perspective of professionals. Methods Twelve individual interviews with professionals in social services, healthcare and voluntary organisations were conducted. Data was analysed with content analysis.    Results Professionals’ experience that collaboration for care and support for women in homelessness with co-morbidity often works poorly. Organisations work in isolation without a holistic view; responsibilities are passed around and no one takes a coordinating approach. The woman is not listened to or the centre figure, due to bureaucratic language and that professionals control the agenda. Meetings are planned without regard to the woman's actual life situation with illness, substance abuse and homelessness, which hinders her participation. Professionals also expressed that women are an especially vulnerable group, who experience shame about their situation and may be exposed to violence. The co-morbidity is severe and there is focus on care, but not the violence. For collaboration and participation to work, it is necessary to put the woman at the center, adapt to her needs and situation, with a clear purpose, understandable content and the opportunity for preparation and follow-up. A support person, who helps coordinate and guide through the process, can be crucial. It is also important to create trust, show respect, and build a relationship over time. Conclusion Intersectoral collaboration in the provision of care, support, and participatory opportunities requires committed, flexible and empathetic professionals, who work together acknowledging all aspects of the individual woman’s circumstances - not their own organisational framework.