This study investigates the impact of providing teacher feedback on answers to guiding questions in the online environment of a flipped classroom setting. Participants were second year bachelor students enrolled in the "Invertebrates" courses (N = 104) at the School of Education in CanTho University (Vietnam), and were randomly assigned to two research conditions: (1) With extra feedback (WEF, n = 52) and (2) No extra feedback (NEF, n = 52) in a flipped classroom setting. One way repeated measure ANOVA was used to analyze learning performance, self-efficacy beliefs, and appreciation of feedback. The findings reflect significantly higher learning performance of students studying in the WEF-condition. In addition, significant changes were observed in their self-efficacy beliefs and appreciation of feedback.