Background: Currently, in the scientific literature there is a great interest on the study of strategies to implement patient-centered care. One of the main tools for this is the therapeutic relationship. Some studies suggest that the perception of the environment in which the treatment takes place can influence the perception of its quality, but this is not explored in physical therapy. For all these reasons, the aim of this study was to understand the influence of the environment in which physical therapy treatment takes place on the patients’ perception of the quality of the patient-centered therapeutic relationship in public health centers in Spain. Methods: A qualitative study analysed thematically using a modified grounded theory approach. Data collection used semistructured interviewing during focus groups. Results: We conducted four focus groups. The size of the focus groups ranged from six to nine participants. In total, 31 patients participated in these focus groups. Participants described a series of specific experiences and perceptions relating to the environment, which they felt were influential in the establishment of therapeutic patient-centered relationships, including six physical factors (Architectural barriers, Furniture, Use of the computer, Physical space, Ambiet conditions, and Privacy) and six organizational factors (Patient-physical therapist ratio, Treatment interruptions, Social factors, Continuity with the professional, Lack of professional autonomy, and Coordination or communication among team members). Conclusion: The results of this study highlight environmental factors that affect the quality of the therapeutic patient-centered relationship in physical therapy from the patient’s point of view, and emphasize the need for physical therapists and administrators to underline the need to review these factors and take them into account in their service delivery.