ObjectivesThis study aimed to identify the individual- and community-level determinants of mothers’ healthcare-seeking behaviour for children under the age of 5 years with acute respiratory infection (ARI) symptoms in low-and middle-income countries (LMICs). Study designNationally representative Demographic and Health Survey datasets from 29 LMICs were used. MethodsThe study included 16,893 children aged under 5 years with ARI symptoms in the 2 weeks prior to the survey. A multilevel logistic regression model was used to examine associations between individual- and community-level factors with health-seeking behaviour for ARIs. The adjusted odds ratio (AOR) along with 95% confidence intervals (CIs) were reported as a measure of association. ResultsThe overall prevalence of healthcare-seeking behaviour for ARIs among children under 5 years in LMICs was 58.83% (95% CI: 58.08, 59.57). Findings showed that mothers with primary or higher education (AOR = 1.20; 95% CI: 1.08, 1.33), and those residing in rich households (AOR = 1.32; 95% CI: 1.18, 1.48), attending antenatal care (ANC) visits (AOR = 1.53; 95% CI: 1.31, 1.79) and delivering at a healthcare facility (AOR = 1.28; 95% CI: 1.16, 1.41) were more likely to seek healthcare for ARIs. A higher level of community maternal education (AOR = 1.44; 95% CI: 1.24, 1.68) was positively associated with seeking healthcare for ARIs, while a higher level of community poverty (AOR = 0.83; 95% CI: 0.72, 0.96) was negatively associated with healthcare seeking for ARIs. ConclusionsThis study revealed that mothers’ healthcare-seeking behaviour for ARIs was closely linked to modifiable risk factors, including maternal education, household wealth, use of maternal health services (e.g., ANC), as well as community poverty and literacy levels. Future interventions should consider these modifiable risk factors when developing strategies to improve child health outcomes in LMICs.