An interval graph is a type of graph that represents a set of intervals on a line. Each interval corresponds to a vertex, and an edge is drawn between two vertices if their intervals overlap. This means that if two intervals share any part of their length, they are connected by an edge in the graph. Interval graphs are useful in various applications, such as scheduling problems and resource allocation. They can be efficiently represented and analyzed using algorithms, making them a valuable tool in fields like computer science and operations research.