Background: Among students, little is known about the physical and social context of eating lunch. The objective of this study was to determine if food intake (including the type of food and beverages and portion sizes) was associated with specific aspects of the physical and social lunch environment (location, with whom lunch was consumed, who prepared the food, and where the food was originally purchased). Methods: A total of 1236 participants (males = 659, females = 566) in grades 6 (n = 359), 7 (n = 409), and 8 (n = 463) from southern Ontario, Canada, completed the Food Behavior Questionnaire during the 2005-2006 academic year. Results: A total of 8159 foods and 2200 beverages were consumed during the lunch meal, which contributed to 552 kcal (SD = 429) or 30% (SD = 16) of total daily energy intake (kcal/day). Higher amounts of energy, meats and alternatives, other foods, fried foods, and pizza were consumed when participants ate in between places or at a restaurant/fast food outlet (compared with at home or school, p less than 0.05) and/or when prepared by friends or others (compared with themselves or family members, p less than 0.05). A large number of participants (46%) reported consuming sugar-sweetened beverages during lunch, despite a school board-level policy restricting the sales of "junk food," which appears to be brought from home. Conclusions: Our findings support schools in policy efforts that restrict fast food access (by leaving school grounds, preventing fast food companies from coming onto school grounds, or restricting sugar-sweetened beverage sales in vending machines) and that eating in between places should be discouraged. (Contains 3 tables.)