The purpose of this study was to investigate the influence of a writing intervention on the writing and reading achievement of middle school students. Specifically, this study was concerned with 6th grade students who were exposed to a writing intervention and those 6th grade students who were not exposed to a writing intervention with regards to their writing fluency, reading-writing achievement and reading comprehension. Secondly, this study investigated the influence of the demographic factors of gender and ethnicity on the writing fluency, reading-writing achievement and reading comprehension scores of sixth grade students. A Non-Equivalent Control Group Design was employed in the study. A random sample of 156 6th grade students attending an intermediate school located in an urban school district in the Southern region of Texas. Three instruments entitled The Writing Fluency CMB, Written Narrative Composition and the Reading Sixth Grade Assessment were employed to gather the data for the study. All the three investigative instruments had excellent content validity. Among the conclusions of this study, it was determined that the writing intervention program did not influence the writing or reading achievement of the students who were exposed to dialogue journal writing. Sixth grade students who were exposed to dialogue journal writing performed similarly to those who were not exposed to dialogue journal writing. African American sixth grade students were found to have significantly higher writing achievement scores than their Hispanic counterparts. Male and female sixth grade students were found to have similar writing and reading scores. Even though, statistically significant differences were not found between the writing and reading performance of sixth grade student; female students had higher mean writing and reading scores than their male counterparts. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]