In order to effectively support students' learning and development at university, we need a better understanding of what helps undergraduate students thrive in the university environment. In this study, we surveyed 204 senior undergraduate students at a large research-intensive university in western Canada to explore factors related to thriving as a university student. We measured sense of belonging (including perceived faculty understanding, peer support, and classroom comfort), task value (students' perceptions of the value of their course content), and academic achievement (self-reported grade point average) for students' current year and their recollections of their first year at university. We also asked students to identify factors they considered integral to becoming a successful university learner. Both sense of belonging and perceived task value increased from first to senior year. Sense of belonging was consistently associated with academic achievement, whereas task value was associated with academic achievement in first year only. Two components of belonging (faculty understanding, classroom comfort) predicted academic achievement in first year; only one (classroom comfort) predicted academic achievement in the current year. Qualitative analysis of responses to open-ended questions identified themes in four categories as key contributors to students' development and success: personal development, social support, course design, and university resources and opportunities. Factors related to personal development (e.g., learning to prioritize health, improving time management skills, and developing self-regulated learning skills) were identified most frequently as key components in students' adaptation to university learning environments. Insights from this study can inform development of curricular and co-curricular strategies to better support undergraduate students' learning and development at university.