Within the context of exploring an ill-structured task using the Google search engine, this study examined (a) the connections between general epistemic beliefs and the complexity of learners' knowledge exploration processes (i.e., learning complexity) and (b) the role of activating learners' task-oriented epistemic beliefs (i.e., epistemic activation) in affecting their learning processes. Survey was used to collect participants' general epistemic beliefs, and direct analysis of participants' think-aloud protocols documenting their knowledge exploration processes was conducted to measure their learning complexity. Results revealed positive epistemology-learning relationships in the way that learners with complex epistemic beliefs are more likely to invest efforts in integrating knowledge, building flexible knowledge representations, evaluating information credibility, engaging in inquiry, and being learning-oriented during their ill-structured Internet search activities. Epistemic activation seemed to provide an opportunity for learners to contemplate varying advanced strategies to evaluate the quality of web information, trigger their efforts to search for alternative views during learning, and enhance their awareness of task complexity and subjectivity. In addition, learners with complex epistemic beliefs seemed to benefit more from epistemic activation in terms of using advanced strategies for web information evaluation. This research contributes to (a) theoretical understandings of epistemology in connection to learning complexity when learning is open-ended and (b) pedagogical practices of using the epistemic activation strategy to promote deep learning in Internet-based learning environments.