Focusing on thinking skills which are basic to citizenship, the paper reviews definitions of citizenship from Plato to the present, discusses scholarly thinking about citizenship, lists general principles of skill development, and presents two brief sample lessons. Citizenship is interpreted as social interaction which is based upon global responsibility as well as social conscience. Eight general principles of mental and physical skill development are identified, including skills developed through logical and organized activities; skills maintained through practice; and skills improved through practice and teacher feedback. The process for developing citizenship skills will vary according to student interests and available class time but should include an introductory stage to motivate students; a development stage in which the teacher demonstrates the skill and allows students to practice the skill; a student and lesson evaluation phase; and a reteaching stage which encourages all students to achieve acceptable proficiency. Two sample lessons are presented. The first is a 6th grade consumer economics lesson which requires students to analyze differences between fact and opinion. The second is a lst grade lesson on families which illustrates how students can classify objects and experiences into logical categories. Learning activities include class discussion of photographs and statements, written exercises based on newspaper adds and magazine illustrations, group discussion, and art work. An outline of 19 primary intellectual skills and six advanced intellectual skills is presented. (Author/DB)