This paper describes the development of the AntConc corpus analysis toolkit, originally designed for use in a technical writing course at Osaka University, Japan, but now adopted in institutions throughout the world as an easy-to-use, freeware, multiplatform alternative to the many commercial concordance programs. First, I will explain how the software was originally tailored to the needs of students in the Osaka writing course and later to a general audience through the requests and feedback from teachers and students around the world. Then, I will give an overview of tools in the most recent version of AntConc and explain their value using examples from the classroom. Finally, I will discuss some of the software's limitations and future developments, and suggest applications in professional communication