The purpose of this dissertation is to examine the impact of multimorbidity and financial resources on psychological well-being in later life. Three research studies were conducted using data from the Health and Retirement Study (Studies 1 and 2) and the Georgia Centenarian Study (Study 3). Study 1 examined the longitudinal effects of multimorbidity on initial levels of wealth and depressive symptoms and the change in wealth and depressive symptoms over four time points. The growth curve analysis revealed that older adults presenting multimorbidity or higher number of chronic diseases and illnesses had significantly lower levels of initial wealth and higher levels of initial depressive symptoms. In addition, multimorbidity had a negative association with the linear change in wealth and a positive association with the linear change in depressive symptoms. The results indicate that older adults with a higher number of chronic diseases and illnesses experienced a linear decline in wealth and a linear increase in depressive symptoms. Study 2 examined the effects of multimorbidity and financial resources on depressive symptoms from an individual differences perspective through the five factor personality model. Direct and moderating effects of personality traits were examined. The results indicate that older adults with higher levels of neuroticism, openness to experience, and agreeableness, as well as lower levels of extraversion and conscientiousness reported higher levels of multimorbidity. Older adults with more chronic diseases and illnesses reported less wealth and more depressive symptoms. Also, older adults who reported less wealth reported more depressive symptoms. Furthermore, significant indirect effects were found. Multimorbidity had a positive indirect effect on depressive symptoms through wealth. Neuroticism, openness to experience, and agreeableness had a negative indirect effect on depressive symptoms through multimorbidity. Extraversion and conscientiousness had a positive indirect effect on wealth through multimorbidity. This indicates that older adults with higher levels of neuroticism, openness to experience, and agreeableness reported more chronic illness/diseases, which in turn negatively related to wealth. Lastly, three significant interactions were found. Neuroticism moderated the association of multimorbidity with depressive symptoms and extraversion moderated the association of multimorbidity with wealth. Furthermore, age moderated the association between multimorbidity with wealth. Study 3 examined the distal and proximal effects of multimorbidity and financial resources on the psychological well-being of centenarians through the developmental adaptation model. The results indicate that for centenarians, multimorbidity and financial resources did not significantly impact their psychological well-being. However, their perception of financial adequacy had a significant impact on their experience of negative emotions. In addition, years of education had a stronger impact on perceptions of financial adequacy. The findings from the three studies provide support to previous literature and contribute to the literature on the importance of examining the impact of multimorbidity and financial resources on psychological well-being in later life.