Purpose To develop a clinical standard set of outcome measures that are accepted for relevance and feasibility by stakeholders and useful for (a) interaction between patient and the professional, e.g. shared decision-making in goal-setting, monitoring and feedback based on outcomes, (b) internal quality improvement, and (c) external transparency in patients with non-specific low back pain (NSLBP) in primary care physical therapy. Methods We used a consensus-driven modified RAND-UCLA Delphi method in seven steps with panellists (patients, representatives of patient and physiotherapy associations, researchers, policy makers, health insurers): (1) literature search, (2) first online survey, (3) patient interviews, (4) an experts meeting, (5) a consensus meeting, (6) second online survey, and (7) final approval of an advisory board. Steps 1-4 resulted in potential outcome measures. In the consensus meeting after discussion panellists voted for inclusion per measure. In the second online survey the final standard set was rated on relevance and feasibility on a 9-point Likert scale; when the median score was ≥ 7, the standard set was accepted and finally approved. Results Thirteen draft outcome measures were rated and discussed, and finally, six outcome measures were accepted. The standard set includes the Quebec Back Pain Disability Scale, Oswestry Disability Index, Patient-Specific Functional Scale, Numeric Pain Rating Scale, Global Perceived Effect (GPE-DV), and the STarT Back Screening Tool (SBT). Conclusion This study presents a standard set of outcome measures for patients with NSLBP in primary care physiotherapy accepted for relevance and feasibility by stakeholders. The standard set is currently used in daily practice and tested on validity and reliability in a pilot study.