Vocabulary knowledge is highly correlated with reading comprehension and overall academic success. Oxford Dictionaries defines vocabulary as “the body of words used in a particular language” (Oxford Dictionaries, 2013, para. 1). Vocabulary knowledge can be demonstrated in two ways: receptively or expressively. Knowledge of the words we see and hear would be described as the individual's receptive vocabulary. Expressive vocabulary consists of words used to convey information, whether by writing or speaking. Typically, receptive vocabulary is larger than expressive vocabulary. Although individuals may understand the general idea of ​​a word in their receptive vocabulary, they may not have the knowledge of the true definition that would be necessary to use the word in their expressive vocabulary (Kamil & Hiebert, in press). Vocabulary development is important for a number of reasons. Developing children's vocabulary is important from an early age. Studies have shown that children who read regularly have larger vocabularies and better success decoding words while reading (Burgess, Hecht, & Lonigan, 2002). Children's vocabulary at age three is a strong predictor of their language and reading comprehension in third grade (Hart & Risley, 1995). Additionally, children with poor vocabulary skills have been shown to have difficulty understanding reading. Not only does vocabulary play a crucial role in reading comprehension, but it is also highly correlated with academic success (Lehr et al., 2004). As students advance through the levels, the vocabulary needed to succeed in higher grades becomes broader. Typically, academic vocabulary prompts appear in books for 3rd and 4th graders (Chall, Jacobs, and Baldwin,......middle of paper......ice activities for spelling words involving each unit. These activities include completing sentences, identifying misspelled words, adding prefixes, adding suffixes, and completing sentences. Students' vocabulary knowledge will be assessed expressiveness of current vocabulary words. These results will be compared to standardized vocabulary measures to determine the relationship to general vocabulary ability. The following questions will be explored: 1. Do 4th grade students in Grand Forks Public Schools learn vocabulary using Reading Street curriculum??2. 4th grade students' weekly spelling word vocabulary knowledge correlates with general vocabulary skill (PPVT, EVT)