People experience uncertainty in every aspect of life and researchers have investigated the concept in domains of psychology and communication in various contexts such as decision-making, health contexts, business, organizational settings and relational issues. Uncertainty is also a key concept in educational settings as it is unavoidable in life and it is a natural characteristic of learning contexts.Thus, it seems significant to expand our understandings of how students experience uncertainty while language learning. From the complex dynamic systems perspective, language learning is characterized as meaning making and this process of meaning making involves uncertain situations. This study was designed to investigate how language learners experience uncertainty; that is how they appraise uncertainty and how they feel in uncertain situations. As the language classrooms are emergent, selforganizing systems, uncertainty stems from various sources in different forms. In order to find out about language learners' uncertainty experiences multiple data sources were employed. The results revealed that uncertainty was a pervasive experience for language learners. They experienced uncertainty related to the course, cognitive processes, and social factors and they develop positive and negative appreciations of uncertainty.