This dissertation investigates the actual versus perceived knowledge of oral language development strategies among early years teachers in international schools. Employing Prestwich's (2012) "Teacher's Knowledge of Oral Language Development" (TKOLD) survey, it assesses teachers' knowledge in critical areas such as promoting extended discourse and the use of specific vocabulary and rare words to promote oral language development with young learners. This research, the first of its kind among international school early years teachers, collected demographic data and actual and perceived knowledge of strategies to support oral language development. Though the survey response rate was lower than desired and did not reveal statistically significant findings the responses did show some disparity between what teachers know and believe they know. The data recommends further studies and advocates targeted professional development training in specific deficit areas to narrow this knowledge gap. In conclusion, this study did not find substantial evidence to support any of the hypotheses. However, some moderate effect sizes and trends suggest potential areas for further research. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]