Current vocabulary instruction in first and second grade classrooms does not adequately prepare students for future grade-level reading material. This study examined the effect of using Latin and Greek roots to increase word knowledge. In this study, students in an experimental group were taught Latin and Greek roots using a Word Family Tree graphic organizer. A control group of students was not directly taught Latin and Greek roots. Each group took a vocabulary pretest and posttest to assess their knowledge of Latin and Greek roots during the first and last week of the study. The mean difference scores for the experimental group were compared to the mean difference scores for the control group using a t-test of means for independent samples. Results of Levene's Test of Equality of Variance indicated the appropriate modified t-statistic as t, confirming the difference between the groups was a result of the treatment. These findings indicate using the Word Family Tree graphic organizer to introduce Latin and Greek roots to first and second graders can enhance word knowledge, and support teaching Latin and Greek roots to young children as a transferable skill which students may continue to use throughout their lives. Knowledge of Latin and Greek roots has been considered only appropriate for students in the intermediate grades and above; however, words containing Latin and Greek roots are abundant in primary students' oral vocabularies and can be useful to enhance word knowledge. Implementing word knowledge strategies in the primary grades has significant implications for social change as these strategies can help construct a foundation that will allow students to excel academically and become life long learners who can effectively contribute to society.