Reading instruction for older students with reading difficulties is a topic increasingly in need of well-informed support and research-based guidance. Recent reform efforts have resulted in positive literacy results in the primary grades, but far too many students are advancing to secondary schools without the prerequisite literacy skills to be successful in history, literature, mathematics, and science. The purpose of this study was to examine trends and differences that exist in vocabulary and reading comprehension mean scores over a period of nine months. The study determined if differences exist in mean gain vocabulary scores and mean gain reading comprehension scores as measured by Istation’s Indicators of Progress (ISIP) Advanced Reading; and vocabulary and reading comprehension scores were examined to determine if significant differences exist in vocabulary and reading comprehension beginning of year and end of year scores of students receiving guided reading and students receiving direct instruction as their reading approach. This study utilized archived ISIP Advanced Reading vocabulary and reading comprehension scores from 237 fifth grade students in one large urban school district during the 2013-14 school year; 119 students were taught by two teachers who utilized Guided Reading as an instructional approach in one elementary school and 118 students were taught by two teachers who utilized Direct Instruction as an instructional approach in another elementary school. Data treatment and analyses were divided into three phases including: 1) examining trends in mean vocabulary and reading comprehension scores of students instructed using guided reading and students instructed using direct instruction over a nine month period of time; 2) conducting independent t-tests to examine if there are significant differences in beginning of year and end of year vocabulary and reading comprehension mean gain scores in each of the classes that utilized the guided reading approach and each of the classes that utilized the direct instruction approach; and 3) conducting an ANOVA test to compare differences that exist in the vocabulary and reading comprehension mean gain scores among classes that received the guided reading approach and classes that received the direct instruction approach. The findings of this study revealed important differences in student performance gains, from beginning of year to end of year, for those taught using the guided reading approach and those taught using the direct instruction approach for both vocabulary and reading comprehension. Both direct instruction classes had statistically significant and medium size gains in vocabulary and reading comprehension (with large size vocabulary gains in one of the Direct Instruction classes), whereas only one of the Guided Reading classes had statistically significant gains in their vocabulary scores, although not in reading comprehension scores. When comparing scores from the beginning of the year to the end of the year, results revealed that students taught with direct instruction exhibited significantly greater gains in both vocabulary and reading comprehension scores than those taught with guided reading approaches. In addition, comparing mean gains scores across instructional methods and classes, it is evident that one of the Direct Instruction classes had the largest gains in the vocabulary scores during the 2013-2014 academic school year, while both direct instruction classes had moderate size gains in comprehension. Findings from this study may be used to inform school and district leaders how guided reading and direct instruction impact achievement gains in vocabulary and reading comprehension among fifth graders. These findings may also assist school leaders in their decisions regarding the appropriate reading programs to implement for students from similar school contexts.