Objective: Individuals diagnosed with low risk, localised prostate cancer (PCa) face a difficult decision between active surveillance (AS) and definitive treatment. We aimed to explore perceived influences on treatment decision-making from the patient and partner's perspectives.Methods: Patients (and partners) who met AS criteria and had chosen their treatment were recruited. Semi-structured individual interviews were conducted via telephone to explore experiences of diagnosis, impact on patient lifestyle, experiences with physicians, treatment preferences/choice, treatment information understanding and needs, and overall decision-making process. Interviews were audio recorded, transcribed verbatim, and analysed using Reflexive Thematic Analysis.Results: Twenty-four male patients (18 chose AS) and 12 female partners participated. Five themes relating to social-ecological influences on treatment choice were identified: (1) partner support and direct influence on patient treatment choice,(2) patient and partner vicarious experiences may influence treatment decisions,(3) the influence of the patient's life circumstances, (4) disclosing to wider social networks: friends, family, and co-workers, and (5) the importance of a good relationship and experience with physicians. Additionally, two themes were identified relating to information patients and partners received about the treatment options during their decision-making process.Conclusions: A range of individual and social influences on treatment decision-making were reported. Physicians providing treatment recommendations should consider and