Background: Children's mental ill-health is a growing public health problem that places demands on adults around the child. However, research shows that healthcare professionals can experience uncertainty when meeting children with mental ill-health. By exploring the experiences of healthcare professionals in primary care working with children affected by mental ill-health, factors influencing relationships and the quality of care can be identified. This knowledge may strengthen both healthcare professionals and other important adults in their efforts to provide adequate support to the child.   Aim To explore Healthcare professionals’ experiences of creating relationships with children with mental ill-health. Methods: A qualitative methodology was employed to explore experiences from 16 Swedish health care professionals working in primary care with children affected by mental ill-health. Data were gathered through face-to-face meetings and videoconferencing between February and August 2025, using a semi-structured interview approach. A thematic analysis, grounded in descriptive phenomenology, was conducted. Findings: The data analysis emerged into four primary themes: The physical space of the encounter, Creating a safe space, Communication strategies for interaction and Supporting children’s capability. Healthcare professionals perceive encounters with children experiencing mental ill-health as shaped by physical settings and the dynamics between child, parent, and professionals. Establishing a safe space through communication strategies is described as fundamental. Key aspects include building trust, showing empathy, listening without judgment, and supporting the child in making sense of feelings. Professionals emphasize the importance of strengthening children’s capabilities and resources, while partnering with parents to ensure sustained support and recovery. Discussion: Creating sustainable relationships requires knowledge of the importance of the child’s lived space and communication strategies. A child-centered perspective can guide the development of timely and appropriate support, ensuring care that meets children’s needs effectively. The study contributes scientifically by clarifying how healthcare encounters with children experiencing mental illness can be improved.