Mindfulness is a form of mental training wherein metacognitive awareness, attention control and an attitude of non-reactivity are cultivated. Applied to managing of emotions, mindfulness can be considered an emotion regulation strategy. Only a few developmental studies explored the direct link between mindfulness and emotion regulation and they were limited to Western cultural context. Additionally, no studies investigated the underlying neurodevelopmental mechanisms of mindful emotion regulation. This randomised controlled study with an active control group (N=200) will be the first to investigate the impact of mindfulness training delivered as part of regular school curriculum on emotion regulation of primary school children from a cross-cultural perspective (in Vietnamese context). The study will integrate electrophysiological (event-related brain potential) and novel first-person assessments (self-interpreted narratives) with self-report and informant-report measures. The electrophysiological assessments will focus on P300 and LPP components (P300 is sensitive to emotion processing and the LPP indexes emotion regulation strategies and cultural factors). The mindfulness curriculum (called The Present) will be delivered to pupils by their own school teachers who have been previously trained in mindfulness and delivery of the curriculum. The findings will provide pioneering evidence regarding neurodevelopmental impact of mindfulness on emotion regulation under a particular cultural context.