Psychological well-being is an influential factor for healthy aging, and noncommunicable diseases usually accompany aging. Therefore, understanding factors predicting psychological well-being is essential to designing interventions to promote good mental health among this population. This cross-sectional study examined the factors predicting psychological well-being among older adults with noncommunicable diseases. The participants included 110 older adults aged 60 years and older with noncommunicable diseases who were receiving services in the outpatient department of medicine of a university hospital in Bangkok. Thailand. Instruments for data collection were a Demographic Questionnaire, the Barthel Activities of Daily Living Index, the Self-Esteem Questionnaire, the Social Support Questionnaire, the Thai Geriatric Depression Scale (TGDS-15), and the Psychological Well-Being Questionnaire. The data was analyzed using multiple regression analysis, Spearman's rank correlation coefficients, and descriptive statistics. The results showed that the participants had high scores on psychological well-being. Activities of daily living, self-esteem, social support, and depressive symptoms collectively predicted 61.2% of the variance in psychological well-being. Social support had the highest predictive power, followed by activities of daily living, depressive symptoms, and self-esteem, but the duration of the disease could not predict psychological well-being. The results of this study are beneficial for gerontological nurse practitioners and others to screen for factors affecting the psychological well-being of older adults with noncommunicable diseases. They can also use the findings to design and test the effectiveness of the intervention program's emphasis on increasing social support, activities of daily living and self-esteem, and decreasing depressive symptoms among older adults with noncommunicable diseases.