This experimental study investigates the effects of using NotebookLM on students’ academic achievement and students’ assessment of NotebookLM in online digital literacy courses in higher education. It was conducted using an explanatory sequential mixed-methods design. A one-group pretest–posttest model was employed. During a five-week intervention, 33 Turkish students used NotebookLM for summarizing, concept mapping, and scenario-based problem-solving activities. Data was collected from a pretest, posttest, and interviews. Quantitative data was projected into SPSS 27 for analysis, and qualitative data was thematically analysed. Results reveal a significant difference between the pretest score (M = 66.90, SD = 10.26) and posttest score (M = 74.90, SD = 13.16) in terms of academic achievement, t(32) = −3.51, p = 0.001. The effect size was moderate (Cohen’s d = 0.68). Interview data shows that the students perceived NotebookLM as helpful for comprehension, time efficiency, motivation, and feedback, though constrained by language support and occasional technical problems. The findings suggest implications for using NotebookLM in online courses in higher education in Turkey.