Teacher knowledge enhances instruction. Of particular importance for spelling instruction is literacy-related content teacher knowledge. This knowledge includes awareness of individual speech sounds, syllables, and morphemes in the English language. Teachers who possess this knowledge are better able to assess student needs and design instruction that meets those needs so that students learn to spell well. In this study, 36 preservice teachers and 38 inservice teachers completed a survey and three measures. The survey asked teachers to calibrate their knowledge of phonemic awareness, phonics, and spelling. The measures assessed the teachers’ literacy-related content knowledge and their ability to use this knowledge to analyze student spelling errors and choose appropriate instructional activities to meet student needs. Overall, the preservice teachers were more positive in their assessments of their literacy-related content knowledge while the inservice teachers demonstrated greater literacy-related content knowledge. Neither group was adept in analyzing students’ spelling errors although the inservice teachers were better able to choose appropriate instructional activities.