<p>In this article, by deriving detailed consequences from the Kantian principle of treating people as ends in themselves, I propose how it works through the psychological constructs of self-acceptance and self-concept development. Unconditional self-acceptance, based on non-judgmental awareness of thoughts and feelings, is important in education and therapy; inspired mainly by Albert Ellis, I ask whether and how it is possible to combine unconditional self-acceptance with self-knowledge and self-assessment within an ethical framework. After presenting the determinants of self-relating, I analyse the popular concept of self-esteem: whether it promotes a person’s development and is logically and philosophically defensible. There is a risk of confusing egoic protection of one’s self-esteem with personal development, and there are other dangers with self-esteem that I present in the light of mindset theory. I instead describe the forms of self-evaluation consistent with the attitude of self-acceptance: honest knowledge of one’s own acts and its instrumental and non-instrumental value, while resigning from an overall evaluation of the self. As an alternative source of self-worth, I present approaches basing it merely on the personal existence. Finally, by formulating practical implications for education and for research, I suggest unconditional self-acceptance can be the basis of a new educational ethics, moving away from misleading and perfectionistic self-concepts.</p>