The experiences of a variety of postsecondary institutions using different academic calendar options are examined. Several calendar options are described: the traditional semester, the early semester, 4-1-4, the quarter system, the trimester plan, composite plans, and year-round plans. The traditional semester calendar begins in mid-September and has one semester running until late January and another from late January through early June. In the early semester calendar the first semester runs from late August through mid- to late December, and the second semester continues from mid-January to late May. The quarter system is comprised of four 12-week sessions. The trimester system uses a calendar of three 16-week sessions. The 4-1-4 schedule consists of three sessions: 16 weeks, four weeks, and 16 weeks. Year-round institutional calendars are characterized by continuous operation. The various types of institutions that use each of these plans, and advantages and disadvantages of each plan are discussed. It is suggested that the academic calendar has become an important element in faculty affairs and collective bargaining. The need for a thorough analysis of academic calendar use in postsecondary education is emphasized as a key to successful use of scheduling and good academic management. (Author/SF)