Unhealthy sleep patterns and accelerated biological age are frequently associated with multiple chronic respiratory diseases (CRDs), including COPD, asthma, and interstitial lung disease (ILD). However, few studies have explored the role of biological age in the relationship between sleep patterns and CRDs.To explore the association between sleep patterns and CRD, and the extent to which biological age mediates the relationship between sleep patterns and CRD.This was a prospective cohort study based on UK Biobank. The sleep score was derived from five self-reported sleep traits: sleep duration, daytime sleepiness, chronotype, snoring, and insomnia. The score ranged from 0 (least healthy) to 5 (healthiest). Biological age was represented by PhenoAgeAccel.Among 303,588 participants, 11,105 (3.7 %), 9,380 (3.1 %), and 1,667 (0.5 %) were diagnosed with asthma, COPD, and ILD, respectively. Each 1-point increase in the sleep score was associated with a 0.156-year reduction in PhenoAgeAccel, and 14.3 %, 12.4 %, and 6.7 % reduction in asthma, COPD, and ILD, respectively. For each 1-year increase in PhenoAgeAccel, the risk of asthma, COPD, and ILD increased by 2.8 %, 4.3 %, and 5.7 %, respectively. PhenoAgeAccel mediated the associations between the sleep score and asthma, COPD, and ILD, with a mediated proportion (95 % CI) of 2.81 % (2.35 % to 3.27 %), 4.94 % (4.23 % to 5.66 %), and 12.48 % (10.43 % to 14.53 %), respectively.A better sleep score was significantly associated with younger biological age and decreased risk of CRDs, with biological age playing a mediating role in the association between sleep score and CRDs.Copyright © 2024 Elsevier Inc. All rights reserved.