This chapter examines age differences in political participation in democratic societies by addressing a number of key questions. The first part of the chapter is dedicated to the question of when people start to develop political attitudes and behaviors and why the timing of these first-developed attitudes and behaviors is important. The second section of the chapter addresses whether early political experiences persist in later life (in other words whether political behavior is habitual) or whether these early experiences are over-written by newer experiences. The third section of the chapter focuses on what we know about aging and political behavior, and how the behavior of young people differs from that of older citizens. The final part of the explores the challenges and opportunities for research on aging: Which are the pivotal questions that are still unanswered? What new avenues of research merit attention?