The purpose of this study was to investigate the knowledge, misconceptions, and knowledge gaps of Peruvian pre-service teachers (PSTs) and in-service teachers (ISTs). To do so, 112 PSTs and 113 ISTs completed the Knowledge and Beliefs About Developmental Dyslexia Scale (KBDDS). Results show that ISTs scored significantly higher than PSTs. Moreover, misconceptions and lack of information were higher in PSTs. The most noteworthy misconceptions were that dyslexia is due to poor visual perception and that letter or word reversals are the most important criterion in the identification of dyslexia. Age, years of teaching experience, prior exposure to a child with dyslexia, and self-efficacy were positively correlated with knowledge about dyslexia in ISTs.