Non-alcoholic fatty liver disease (NAFLD) parallels comorbidities such as metabolic syndrome, dyslipidaemia or diabetes. Although NAFLD is very prevalent in overweight-obese individuals (i.e. body mass index ≥25 kg/m2), recent studies point to the presence of NAFLD in non-obese individuals, for both the Asian (<25 kg/m2) and Caucasian (<30 kg/m2) populations. This paper discusses the pathogenic pathways and current treatment options of NAFLD in non-obese populations. In this respect, non-obese subjects also need to undergo the medical screening for NAFLD. Across the scientific community, we aim to promote the advancement of knowledge in this emerging field.