Students with complex communication needs (CCN) require augmentative alternative communication (AAC) to engage in activities. The American Speech and Hearing Association (ASHA) states that the speech language pathologist (SLP) is the primary professional to conduct AAC assessment and interventions, facilitate team collaboration, and train communication partners. However, SLPs cite challenges to serving AAC users in such areas as knowledge and skill in instructional strategies, vocabulary selection, collaboration skills, and expertise in AAC systems (Allen et al., 2017; De Bortoli et al., 2014; Kent-Walsh et al., 2008). Survey results found SLPs desired practical in-service training that provided specialized knowledge of AAC (DeBortoli et al., 2014). The purpose of this study was to expand the knowledge base by obtaining the level of knowledge, attitude, and usage of AAC among school-based SLPs and provide training in intervention and implementation. Four SLPs participated in the single subject quasi-experimental investigation. Pre/post surveys were used to assess level of knowledge and positivity toward AAC. Frequency of usage of AAC by the SLP were obtained in 15-minute observations. Following three weeks of baseline data collection of usage, a professional development focused on the core vocabulary approach implemented through the descriptive teaching method was provided. Results suggest the intervention was effective at increasing knowledge and usage. No change in attitude occurred. Findings suggest training that includes theory, rationale, strategy description, demonstration, and simulated practice can increase the knowledge and usage of AAC. Keywords: Augmentative and alternative communication, core vocabulary