Developing reading fluency in a first language (L1) is a topic that has received a considerable amount of attention. Developing reading fluency in a second language (L2), however, has received relatively little attention (Grabe, 2009). Anderson (2008) defines reading fluency as "reading at an appropriate rate with adequate comprehension." For adult ESL learners, Anderson suggests a minimum rate of 200 wpm with at least 70% comprehension. Previous studies that have been conducted on L2 reading fluency focus primarily on reading rate development. This study seeks to combine rate development and comprehension development to effectively foster L2 reading fluency. Doing so will provide an answer to the question, what effect does consistent reading fluency instruction have on adult ESL readers in terms of their reading rate and reading comprehension scores? The 362 participants involved in this study are adult ESL students enrolled at the English Language Center at Brigham Young University in Provo, Utah. At the beginning and the end of each semester of the four semester-long study, each participant's reading rate and reading comprehension were evaluated. Each pretest and posttest used for evaluation included a reading passage and comprehension questions. The reading passages in each test were level appropriate with the posttest always being more difficult than the pretest to account for the natural learning that takes place during the duration of a semester. In between the pretest and posttest assessments, reading teachers were asked to implement one rate development activity or one comprehension development strategy on a daily basis. The results from the McNemar procedure support the hypothesis that consistent reading fluency instruction effectively builds reading fluency by positively influencing rate development and comprehension development (p < .001374). The majority of the participants were not able to attain Anderson's (2008) standard of reading fluency by reading 200 wpm with 70% comprehension. Of the 362 participants that received one semester of treatment, 52 (14.36%) reached Anderson's standard of fluency. Of the 139 participants that received two semesters of treatment, 31 (22.30%) reached Anderson's standard of fluency. An analysis of reading rate and reading comprehension scores shows that the average participant, although still not considered a fluent reader, made notable progress toward fluency. Implications of these results, limitations, and suggestions for future are discussed at the conclusion of this thesis.