This mixed methods cross-sectional survey study framed in amalgamation theory (Ehri, 2020) and the Simple View of Reading (Gough & Tunmer, 1986) explored the ways in which k-2 general classroom teachers define, understand, and teach sight word development through an orthographic mapping lens. The study utilized a convergent parallel design to concurrently analyze, merge, and compare the quantitative online survey results of 624 teacher responses explicated alongside the perspectives of 15 teacher interviews. A constant comparative analysis of the open-ended responses identified three key recurring sight word definitions: any word recognized instantly (38.5%), a phonetically irregular word (16.8%), and a high frequency word (HFW) (13.1%). Approximately a third of the total participants agreed with at least two or more sight word definitions. Further analysis of open-ended responses identified 45 daily "essential" sight word classroom practices with about a third of the practices aligned to orthographic mapping principles (n = 219). Statistically significant differences were found for sight word definitions and instructional frequencies with medium to large effect sizes among responses aligned to orthographic mapping principles. Teachers in consistent agreement with orthographic mapping principles were also consistent in significantly lower frequency means for teaching irregular HFWs as unanalyzed visual wholes and higher frequency means in applying phonemic awareness training to irregular HFWs. Altogether, triangulated results highlight varied levels of consistencies among specific sight word definitions and practices across teacher beliefs, literacy training/curricula, and schools with larger percentages of at-risk student populations (e.g., Title 1). Teachers trained in Evidence Based Literacy Instruction (EBLI) was the only specialized certification group to report significantly less students struggling in letter-sound correspondences, phonemic awareness, and sight word recognition when compared to other training groups (Orton-Gillingham, LTRS, Calkins). Practical significance taken from the converged database of this study is reason to consider a potential choice overload phenomenon that may have adverse consequences impacting teacher beliefs and optimal practices around sight word development. Recommendations for future research and optimal classroom practice implications are explored. [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.]