INTRODUCTION: Endometriosis is a chronic, systemic condition affecting 5-10% of individuals assigned female at birth. Due to its non-specific symptoms, diagnosis is often delayed. OBJECTIVES: This study aims to explore diagnostic challenges and decision-making processes that general practitioners (GPs) encounter when managing patients with symptoms suggestive of endometriosis in Denmark. METHODS: A qualitative research approach was employed, incorporating the co-production of three fictional clinical vignettes representing diverse endometriosis presentations. Semi-structured interviews were conducted with 27 practicing GPs (7 males and 20 females) from urban and rural areas. Participants had a mean age of 50 years (range 41-66) and clinical experience ranging from newly qualified to 27 years. Interviews involved engagement with the vignettes, and data were analysed using thematic analysis. RESULTS: Findings reveal the challenge of the non-specific nature of symptoms, the role of cyclical symptom patterns in diagnosis, the influence of diagnostic hierarchies, patient-centred care approaches, the bio-psycho-social perspective in management, the persistent stigma surrounding gynaecological symptoms, and GPs limited trust in general gynaecologists. GPs were more likely to suspect endometriosis when symptoms followed a cyclical pattern, whereas gastrointestinal presentations were less commonly linked to the condition. While many GPs adopted a patient-centred, shared decision-making approach, some still adhered to mind-body dualism in their clinical reasoning. CONCLUSION: Diagnosing endometriosis in primary care is challenging due to non-specific symptoms, diagnostic hierarchies, and stigma. Encouraging GPs to routinely inquire about the cyclical nature of symptoms may serve as a valuable diagnostic tool, particularly in cases involving gastrointestinal complaints.