Aim: To identify therapists' views on sexual boundaries and the strategies they employ to manage them in therapeutic practice. Method: In-depth qualitative interviews were conducted with a sample of 13 accredited, experienced practitioners of psychotherapy or counselling. A grounded theory approach, informed by principles from Free Association Narrative methodology, was employed, in which team members used debriefing sessions for extending depth of understanding of the interviews. Findings: There is consensus about boundaries at the extremes, but variability about fantasy, flirtation and touch. A core process was generated from accounts of successful management of sexual attraction. We identified four problematic ways of reacting to boundary pressure, each with potential to harm clients and therapy. Discussion: A participant-observer stance was conceptualised as essential for managing threats to boundaries, consistent with the empathic stance. Minor boundary crossings were viewed by interviewees as both potential precursors of more serious transgressions, and as opportunities for understanding the client's difficulties. Implications for practice: These span training, accrediting organisations, supervision and therapy practice.