Grounded in basic knowledge about human nature and universal needs, the humanistic theory of wellbeing (HTW) proposes that a life is good to the extent that it allows us to perform our humanness well. A well-performed humanness is further defined as the fulfillment of three universal human needs: the need for stability, the need for change, and the need to and for care. Stability is essential for survival, and all biological structures—from DNA molecules to entire bodies and even social groups—need to preserve a high level of orderliness. Homeostasis is a core stability mechanism, but other exists, such as assimilation in the Piagetian tradition or emotional security in Bowlby’s attachment theory. Achieving a goal is also a stability process. The need for stability interacts dynamically with the need for change. Replacing a cell structure, transforming an egg to a chicken, cognitive growth, and improved cultural knowledge are examples of changes that ensure survival. Accommodation in the Piagetian sense and exploration in Bowlby’s theory are also change processes, and the interplay between the safety of a “secure base” and the exploration of new territories is an example of the dynamics between stability needs and change needs. The facilitation of change can be stimulated by reflective judgments originating in wisdom, moral concerns, and a readiness to develop one’s human potentials. Humans are cooperative and dependent. They therefore need to care about each other. Evolutionary, care needs originated with what Churchland calls the “snuggle for survival,” particularly with the intensified orientation toward one’s offspring. This caring orientation was later amplified by selection pressure on sociability. With the birth of human culture, care for others became foundational for the sophisticated social skills that make our humanness possible and unique. For example, when people collaborate toward a joint goal, the wellbeing of all becomes a common concern, and the need to care for each other becomes vital. The relationships between the three universal needs and the wellbeing concepts adopted by the HTW are organized as a hierarchical taxonomy. Concepts identified with stability are referred to as hedonic wellbeing (HWB). Concepts identified with change are referred to as eudaimonic wellbeing (EWB). Care needs intervene on both HWB and EWB. HWB means to be well in the sense of spontaneously like one’s life. HWB comprises two subdimensions: harmony feelings and spontaneous judgments. Prototypical harmony feelings are tranquility, contentment, happiness, and joy. Social feelings such as empathy and love are also harmony feelings. In terms of valence, high levels of pleasure often co-occur with harmony feelings. Spontaneous judgments comprise the thinking element of HWB. The most important indicator of spontaneous judgments is life satisfaction, but domain satisfaction and the presence of meaning in life are also included in this category. EWB means to be well in the sense of becoming a better human being. EWB comprises three subdimensions: opportunity feelings, reflective judgments, and betterment orientations. Prototypical opportunity feelings are interest, engagement, immersion, and wonder/awe. Social feelings such as compassion and romantic love are included as well. Valence is a less salient feature of opportunity feelings, and the levels of pleasure and displeasure vary. Reflective judgments comprise the thinking element of EWB, with wisdom and morality as the most important indicators. In addition to the feeling dimension and the thinking dimension, EWB is further defined by an improvement indicator, referred to as betterment orientations. Personal growth, the search for meaning in life, and a will to be a good human being are important betterment orientations. The taxonomy of humanistic wellbeing accounts for many concepts and their relationships. To summarize them in a definition, HTW suggests that being well means to like one’s life for the right reasons. A life is liked if it feels good and is thought of as good by the person who lives it. The “right reasons” part of the definition is normative and refers to this idea: To count as indicators of a life that goes well, our likings must not violate a small set of humanistic values, specified as respecting basic human rights, avoiding preventable harm, and accepting an ethics of care. The humanistic values are included as background assumptions in the HTW. The values are justified by a combination of empirical evidence—such as the universal need for care—and feminist epistemology. Thus, a value can be regarded as reasonable if it survives the open criticism from a scientific community of peers. From the perspective of feminist epistemology, science is an interactive and social activity. This suggests that new knowledge produces changes in the world and that an altered world in turn provides revised understandings. A humanistic theory of wellbeing is therefore a product of a certain worldview and will hopefully have the potential to contribute to a revised worldview and a better world in return.