This brief suggests that Universities of the Third Age (U3As) provide learning opportunities for older adults. Worldwide, they typically take one of two forms. Based on the first U3A founded in 1973, the French model is university based and offers mostly formal courses. Arising in Cambridge in 1981, the British model emphasizes informal, autonomous self-help groups in which the instructors are usually third-agers themselves. In the United States and Canada, the term U3A is virtually unknown, but the form exists as Institutes of Learning in Retirement (ILRs), begun in 1962. Most of the more than 200 ILRs are linked by the Elderhostel Learning Network. They are community based and often conducted by members; many are affiliated with colleges and universities. Issues that U3As/ILRs must address to sustain their momentum into the 21st century include the following: broadening participation to more diverse groups of elders; exploiting the networking possibilities of the World Wide Web; addressing the intergenerational imperative by encouraging reflection on life experiences and integration of self; and fostering research on aging by third-age participants themselves. (Contains 19 annotations of print resources and contact information for 5 organizational resources.) (YLB)