This chapter covers several aspects of mental and emotional wellness, including sleep and mental health. Most people find sleep to be foundational to their experience of mind-body wellness. Sleep affects almost every process of our body and brain, and if we are not sleeping well, the effects impact our lives almost immediately. Lack of sleep can cause problems with attention, focus, decision-making, depression, and irritability, and chronic sleep deficit is associated with a greater risk of heart disease, obesity, and diabetes. A person does not have to meet the clinical guidelines for a sleep disorder to struggle with sleep and the effects of poor sleep. Mental illness is a substantial dysfunction in a person’s thinking, emotional regulation, or behavior. Mental wellness is more than the absence of mental illness, it is a set of internal attributes that includes a positive outlook, a tendency toward growth and self-improvement, acceptance of the self, a consistent, reliable approach to fulfilling social relationships, and realistic and clear thinking. Mental wellness is dynamic and changes with our environment and circumstances; it allows us to be flexible and proficient in dealing with life’s challenges. The chapter ends with a discussion of ways to treat mental illness and enhance mental wellness.