Companies are starting to produce more and more textbooks in electronic format, which means users, students and instructors, are starting to use this new technology. Many models already exist to explain the factors that influence whether students and instructors adopt new technologies, such as the Technology Acceptance Model (TAM) and the Task-Technology Fit (TTF). TAM is a model for user acceptance of a new technology that demonstrates how usefulness and ease of use directly impact a user's attitude toward using the technology. Being able to measure a potential user's attitude toward using a technology may assist in the development of the new technology by parsing out features that users find useful or not. In a similar vein, TTF is a framework that proposes that there needs to be a "fit" between a users' task and the technology that is being used to accomplish that particular task, otherwise the influences on performance and acceptance will be detrimental. While there are many studies exploring usage of new technologies in the academic domain, such as learning management systems, digital video tools, and e-Books, with TTF, there is only one that explores e-Textbook usage by students (Gerhart, Peak, & Prybutok, 2015). The current study looked to extend the TTF to explore the usage of e-Textbooks among students and instructors, as there are currently no studies that examine e-Textbook usage with both students and instructors. The results from a factor analysis found TTF, Access (to technology), Performance, and Perceived Ease of Use to be the factors for e-Textbook usage. The results from the structural equation model analysis show that Perceived Ease of Use, Access, and TTF impact Performance and Access impacts TTF in e-Textbook usage among students and instructors. The results and implications for future studies are discussed.