Tested the hypothesis of H. Alker and F. Gawin (see PA, Vol 62:8338) that happiness is higher among more psychologically mature individuals and that happiness is qualitatively different for individuals of different levels of maturity. The Loevinger Sentence Completion Test (a measure of developmental maturity), the Bradburn Affect Balance Scale, and 2 additional measures of subjective well-being were administered to 240 men (aged 35-85 yrs). Results do not support the association of maturity with well-being. Further, the personality dispositions of neuroticism and extraversion showed significant relations to happiness regardless of maturity level. It is proposed that developmental level may determine the occasions or interpretations of happiness or unhappiness but that the quality and quantity of the experience of subjective well-being itself is independent of maturity.