Background: Intestinal parasitosis, caused by both helminths and protozoans, are among the most prevalent infections, especially in developing countries. Enteric parasites continue to be a major cause of parasitic diseases which is the most common among street and school going children with poor sanitation. This cross-sectional study was carried out to determine the prevalence and potential risk factors of intestinal parasitosis among school going children of two schools of Saptari district of southern Nepal. Stool samples were collected in a clean, dry, screwcapped, and wide-mouthed plastic container, fixed with 10% formal-saline solution, and transported to the laboratory for further microscopic analysis by following concentration technique. Results: Out of the 285 stool samples analysed, 94 (33%) were positive for the parasitosis. Presence of intestinal parasites was marginally more in rural school (44.6%) than in urban (30%) (P < 0.05). Giardia lamblia was highly prevalent (15.4%) followed by Entamoeba histolytica-like (7.7%), E. coli (7%), Ascaris lumbricoides (1.8%), and Hymenolepis nana (1.08%), respectively. Children of the age group 11-15 years were highly affected (44.2%) compared to younger age groups. The findings of intestinal parasitosis in the study population were statistically significant with family income, hand-washing habit, type of drinking water, and availability of a toilet facility at home (P < 0.05). Over 85% of infection was associated with parasitosis that indicated mainly waterborne infection rather than soil-borne helminths. Conclusions: Poor hygiene measures and farming occupation are identified as major risk factors of parasitic infections, so sanitation especially focusing on safe drinking water along with multi intervention strategies must be emphasized in the Saptari district of Nepal to reduce the burden of parasitic diseases in school children.