Knowledge of lumbar coupling biomechanics is foundational in many manual therapy disciplines. 3-D studies of lumbar coupling indicate that coupling direction may not be predictable. The purpose of this study was to investigate physiotherapists' perception of importance of lumbar coupling for validation of manual therapy, necessity in treatment, and perceived direction of lumbar coupling biomechanics. A sample of 369 physiotherapists within the United States volunteered to participate in this study. An ologit regression analysis investigated factors associated with perception of lumbar coupling. A Fleiss Kappa determined the agreement of coupling direction among physiotherapists. The majority of physiotherapists indicated that lumbar coupling biomechanics were important or very important, frequently used during treatment, and necessary for validation of manual therapy. The ologit regressions identified that the importance placed upon lumbar coupling biomechanics is highly related toward therapists' pre-concept of coupling. Kappa values for the five spinal segments were negative indicating worse than chance agreement: L1-2 = -0.10; L2-3 = -0.11; L3-4 = -0.09; L4-5 = -0.10; and L5-S1 = -0.09. The poor Kappa values, strong pre-conceptual perceptions of coupling necessity, and the importance placed upon lumbar coupling for treatment could lead to disparities among physiotherapists in lumbar manual therapy assessment and treatment.