Academic programs commonly feature a capstone experience as the final building block of the course of study. Often, capstone experiences allow students to demonstrate mastery in the context of an authentic learning experience--a real-life problem or project situated in the field of practice. The growing number of academic programs conducted online raises the question of how distance environments can support an authentic experience in a program capstone. We examine the concept of the capstone, tracing connections to authentic learning frameworks; summarize some of the literature on online capstones; and propose guidelines for structuring online capstones to support rich authentic learning experiences. We then describe two examples of online capstones from our own master's programs, focusing on features highlighted in our guidelines. We conclude that online capstones can satisfy the requirements of an authentic learning model, but must be specifically designed to include critical components of authentic learning, utilizing an array of tools, strategies, good pedagogy, and good design.