1946年の世界保健憲章において世界保健機関（ＷＨＯ）は健康を次のように定義している。
Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.
健康とは、完全な身体的、精神的、社会的な良好な［ある］状態のことであり、それは単に病気や虚弱がない状態だけではない。
この健康の定義は、我が国の学校教育の中にもしばしば登場し、この定義を保健体育の授業で、あるいは試験のために丸暗記された人も多いはずである。
このＷＨＯ憲章はタイプ版で作成されているので、そのオリジナル部分（英語版）を下記に示しておこう。
CONSTITUTION OF THE WORLD HEALTH ORGANIZATION
THE STATES Parties to this Constitution declare, in conformity with the Charter of the United Nations, that the following principles are basic to the happiness, harmonious relations and security of all peoples:
Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.
The enjoyment of the highest attainable standard of health is one of the fundamental rights of every human being without distinction of race, religion, political belief, economic or social condition.
The health of all peoples is fundamental to the attainment of peace and security and is dependent upon the fullest co-operation of individuals and States.
The achievement of any State in the promotion and protection of health is of value to all.
Unequal development in different countries in the promotion of health and control of disease, especially communicable disease, is a common danger.
Healthy development of the child is of basic importance; the ability to live harmoniously in a changing total environment is essential to such development.
The extension to all peoples of the benefits of medical, psychological and related knowledge is essential to the fullest attainment of health.
Informed opinion and active co-operation on the part of the public are of the utmost importance in the improvement of the health of the people.
Governments have a responsibility for the health of their peoples which can be fulfilled only by the provision of adequate health and social measures.
