Civil wars, foreign interventions, and political instability in the Middle East have caused a mass refugee influx since the end of the Cold War. Therefore, how to integrate these refugees into host countries has become a critical question. To answer this question, the existing literature mainly focuses on ethnic and religious diversities, language barriers, and limited access to fundamental services and labor markets. However, there is little focus on case-specific factors to explain the integration dynamics of refugees. This article aims to fill this gap through the analysis of case-specific factors that play a significant role in understanding barriers to integration. This study classifies these factors as follows: geographical proximity, cultural threat, acceptance processes, political rent, and limited economic resources. To understand the influence of these factors, this study assesses refugee flow from Iraq to Syria since the Iraq War of 2003. This study demonstrates that even though Iraqi refugees in Syria were comparatively advantageous in terms of sharing a common language and residing in neighborhoods with common ethnic and religious backgrounds, they could not successfully integrate into Syrian society. This research utilizes the sources of the IOM, UNDP, UNHCR, UNICEF, and WFP to provide a unique analysis.