Objective To compare the efficacy of three slow expiratory airway clearance techniques (ACTs). Design Randomised crossover trial. Setting Tertiary hospital. Participants Thirty-one outpatients with bronchiectasis and chronic sputum expectoration. Interventions Autogenic drainage (AD), slow expiration with glottis opened in lateral posture (ELTGOL), and temporary positive expiratory pressure (TPEP). Main outcomes Sputum expectoration during each session (primary endpoint) and in the 24-hour period after each session. Leicester Cough Questionnaire (LCQ) score and spirometry results were recorded at the beginning and after each week of treatment. Data were summarised as median difference [95% confidence interval (CI)]. Results Median (interquartile range) daily expectoration at baseline was 21.1 (15.3 to 35.6) g. During physiotherapy sessions, AD and ELTGOL expectorated more sputum than TPEP [AD vs TPEP 3.1 g (95% CI 1.5 to 4.8); ELTGOL vs TPEP 3.6 g (95% CI 2.8 to 7.1)], while overall expectoration in the 24-hour period after each session was similar for all techniques (P = 0.8). Sputum clearance at 24 hours post-intervention was lower than baseline assessment for all techniques [AD vs baseline −10.0 g (95% CI −15.0 to −6.8); ELTGOL vs baseline −9.2 g (95% CI −14.2 to −7.9); TPEP vs baseline −6.0 g (95% CI −12.0 to −6.1)]. The LCQ score increased with all techniques (AD 0.5, 95% CI 0.1 to 0.5; ELTGOL 0.9, 95% CI 0.5 to 2.1; TPEP 0.4, 95% CI 0.1 to 1.2), being similar for all ACTs (P = 0.6). No changes in lung function were observed. Conclusions Slow expiratory ACTs enhance mucus clearance during treatment sessions, and reduce expectoration for the rest of the day in patients with bronchiectasis. Clinical Trial Registration Number NCT01854788.