BackgroundHealthy lifestyle behaviors encompass activities aimed at promoting, maintaining, or reclaiming health. Evaluating these behaviors accurately requires comprehensive, valid, and reliable tools.AimsThis study aimed to develop the Healthy Lifestyle Behavior Scale and evaluate its psychometric properties in the Turkish population.MethodsFor this methodological research, a cross-sectional online-based survey was conducted between 21 March 2023 and 31 March 2023 among 330 participants who were recruited via convenience sampling. The initial item pool included 90 items across seven domains (exercise, health responsibility, preventive health actions, sleep, stress and social support, nutrition, smoking, and alcohol). The content validity of the scale was verified by taking expert opinions. Construct validity and reliability were assessed using principal component analysis (PCA) and Cronbach's alpha.ResultsA total of 330 people were recruited for the study (65.2% female, mean age 34.2 ± 9.4 years). The final scale comprised 34 items: 5 on exercise, 4 on health responsibility, 4 on preventive health actions, 2 on sleep, 5 on social support, 3 on stress management, 5 on nutrition, 4 on smoking and 2 on alcohol. The construct validity analysis revealed a 9-factor structure explaining 62.35% of the variance (Kaiser–Meyer–Olkin value = 0.807). Internal consistency was confirmed with Cronbach's alpha (α = 0.863 for the scale, > 0.7 for subscales) and high item-total correlation.ConclusionsOur newly developed Healthy Lifestyle Behavior Scale demonstrated good validity and reliability. It outperformed existing scales, boasting higher alpha values for subfactors and explained variance. This scale is a robust tool for assessing healthy lifestyle behaviors in adults.