This case study examines whether or not an intervention in brain-based learning (BBL) brings about any change in language learning beliefs (LLBs) of adult EFL learners. Students enrolled in an English preparatory program were taught in accord with BBL principles over 16 weeks. Beliefs about language learning inventory (BALLI) was administered at the outset of and subsequent to the intervention in an attempt to explore if English lessons designed in compliance with BBL principles led to changes in EFL learners' LLBs. The findings obtained by running Wilcoxon signed-rank test demonstrated that learning English by attending to lessons planned according to BBL principles induced a statistically significant change in 13 of a total of 34 beliefs in the inventory.