Purpose: This mixed-methods study aimed to obtain information regarding speech-language pathologists' (SLPs) perspectives about treatment of lateralization errors (LEs), challenges to implementing evidence-based LE treatment practice, and the sources SLPs' use to find evidence to treat LEs. This information can assist our understanding of ways to facilitate the uptake of evidence-based practice into the everyday treatment of clients with this disorder. Method: A convergent parallel mixed-methods design was used to collect data from SLPs (N = 214) using 24 questions from an online survey distributed through electronic mailing lists and Speech and Hearing State Associations. Quantitative data were analyzed using frequencies and averages; themes and subthemes of qualitative data were analyzed using a content analysis approach with no a priori codes. Quantitative and qualitative results were compared and integrated. Results: Participants believed that LEs required individualized treatment before the age of 5 years, were largely caused by structural and neuromuscular factors, and required an understanding of orofacial and dental structure and function. Challenges to implementing LE treatment included a lack of skills and knowledge specific to LEs, competing demands on clinicians' time and resources, and a research-practice gap. Sources of evidence frequently used to obtain information about LE treatment were colleagues, trainings, workshops, and American Speech-Language-Hearing Association journals. Conclusions: Clinicians believe that LE treatment is challenging and requires skill training. Future research in LEs will need to consider the real-world decisions clinicians must make when treating this disorder as well as clinicians' everyday constraints and challenges.