Research has shown a wide range of learning benefits accruing from extensive reading. Not only is there improvement in reading, but also in a wide range of language uses and areas of language knowledge. However, few research studies have examined reading speed. The existing literature on reading speed focused on students' reading speed without attending to students' long-term development in reading speed within extensive reading. The study reported in this article was conducted in Shanghai, mainland China with Year-1 senior high school students. It assessed the development of reading speeds of two groups of readers exposed to two different extensive reading treatments--the free reading treatment and the integration reading treatment. Daily reading records displayed the progress in their reading speed. Results show the positive relationship between extensive reading and students' progress in reading speed.