PurposeThe aim of the study was to determine the test-retest reliability of lower limb kinematic waveforms derived from 3D gait analysis (3DGA) in patients following total hip arthroplasty (THA). MethodsEight (7 M:1F; age: 70 ± 7 years; height: 1.68 ± 0.11 m; mass: 85 ± 20 kg) adults with a unilateral THA attended test and retest sessions. 3DGA was undertaken with participants walking at a self-selected pace along a 7 m walkway within each session. The standard error or the measurement (SEM) was calculated for hip, knee and ankle joint angles in all three planes, over the walking gait cycle. ResultsThe SEM ranged from 2.9 to 4.1°, 2.7–3.7° and 1.9–3.9°, in the sagittal, frontal and traverse planes at the hip. At the knee the SEM ranged from 1.6 to 4.2°, 1.0–1.9° and 1.3–2.9° in the sagittal, frontal and transverse planes, respectively. While the SEM ranged from 0.7 to 2.0°, 1.2–2.3° and 2.9–4.0° in the sagittal, frontal and transverse planes at the ankle. ConclusionsThe findings demonstrate that 3DGA provides a reliable means of quantifying lower limb kinematics over the walking gait cycle in patients following THA, with all SEM values below the 5° threshold previously suggested to identify clinically meaningful differences. The SEM values reported may aid in the interpretation of changes in lower limb kinematics in patients following THA.