Objective tools for the assessment of animal welfare are needed. The present study analyzed the interobserver reliability of the Animal Welfare Indicators (AWIN) welfare assessment protocol for horses to further enhance knowledge concerning reliability. Therefore, two trained observers conducted 18 assessments on farm at the same time and on the same animals. The results were compared at individual level by calculation of Cohen's kappa (kappa), weighted kappa (kappa(w)), and prevalence-adjusted, bias-adjusted kappa (PABAK). Spearman rank correlation coefficient (RS), intraclass correlation coefficient (ICC), limits of agreement (LoA), and smallest detectable change (SDC) were used at farm level. The Qualitative Behaviour Assessment was further analyzed by means of principal component analysis. At the individual level, most of the indicators demonstrated acceptable (kappa, kappa(w), PABAK >= 0.4) to good (kappa kappa(w), PABAK >= 0.6) interobserver reliability. Also, at farm level, most of the indicators demonstrated acceptable (RS >= 0.4; ICC >= 0.4; SDC: = 0.7; ICC: >= 0.7; SDC: