Background <p>Low back pain (LBP) remains a leading source of disability and societal cost. In the UK, physiotherapists, osteopaths, and chiropractors are front-line providers of LBP care. Despite widespread dissemination of clinical guidelines, little is known about how their clinical practice has changed over time.</p> Methods <p>We conducted national surveys of UK physiotherapists, osteopaths and chiropractors in 2003 and 2023, using an identical acute non-specific LBP vignette to assess reported use of investigations and interventions at both time points.</p> Results <p>A total of 1,758 eligible clinicians participated in 2003 (834 physiotherapists; 592 osteopaths; and 332 chiropractors), and 1,388 in 2023 (511 physiotherapists; 621 osteopaths; and 255 chiropractors). At both time-points, there were significant inter-professional differences and numerous departures from guideline recommendations. Substantial temporal changes were observed. Physiotherapists shifted towards more restrictive recommendations for work and bed-rest, towards the use of massage, away from spinal mobilization, away from specific exercises, and away from general advice on back care. Chiropractors shifted towards more restrictive recommendations for bed-rest, towards spinal mobilization and acupuncture, and away from spinal manipulation and ultrasound. Osteopaths shifted towards less restrictive recommendations for activity, work, and bed-rest, towards acupuncture, and away from spinal manipulation.</p> Conclusions <p>Between 2003 and 2023, UK physiotherapists, osteopaths, and chiropractors reported evolving management approaches to acute LBP. Substantial inter-professional differences and divergences from guideline recommendations were observed. Some inter-professional differences narrowed over time, suggesting partial convergence of practice.</p>