Background: The Vegan/Vegetarian Athlete's Plate (Veg AP) is a modification of the Athlete’s Plate designed to guide athletes about how to fuel adequately at various training loads on a vegetarian or vegan diet. Objectives: The purpose of this study was to validate and determine the usefulness of the Veg AP among athletes of various competition levels. Methods: Part 1 involved developing 120 vegetarian or vegan “plates” for athletes of different weights at different training loads. Nutrient content of these plates was measured and compared with sport nutrition and vegetarian nutrition guidelines. Part 2 entailed athletes watching a presentation about how to use the Veg AP and then having the athletes create their meals in a university dining hall in accordance with the Veg AP. The appropriateness of the plate was determined by a group of experts. A subset of these athletes participated in a focus group to further ascertain perceptions of the utility of the Veg AP. Results: The Veg AP meets international sport nutrition guidelines for energy and macronutrient content. Micronutrient content of the Veg AP varies, and proper instruction about how best to build plant-based meals to include adequate iron, zinc, and vitamin B12 while avoiding excessive dietary fiber is warranted, particularly to support easier training loads and lighter weight categories. Athlete perception of the Veg AP was that it was educational and helpful for creating a vegetarian or vegan meal that sufficiently supports variable training loads, even for those experienced with vegetarian nutrition. Conclusions: The Veg AP is a useful tool for teaching about vegetarian sport nutrition and providing practical guidance for athletes of a variety of sports and competition levels.