WebTOP is a three-dimensional, Web-based, interactive computer graphics system that helps instructors teach and students learn about waves and optics. Current subject areas include waves, geometrical optics, reflection and refraction, polarization, interference, diffraction, lasers, and scattering. Some of the topics covered are suited for introductory level physics students while others are suited for intermediate optics students. WebTOP is developed with a flexible interface to suit the various needs of instructors and students. Many of the features lend themselves to classroom use or self-guided study. WebTOP is implemented using VRML, Java, JavaScript, and VRML's Java EAI.