To evaluate the nutritional quality, particularly the fat and salt contents, of meals offered to children (kids' meals) at chain restaurants in Japan. A web-based content analysis was conducted to evaluate the type of restaurant, type of meal, incentives, health claims and nutrition data of kids' meals. The nutritional appropriateness of kids' meals was assessed with the Standard for the School Lunch Program, which regulates energy (≤2218 kJ), protein (20-30 g), fat (≤30 % of energy (E%)) and salt (<2 g) contents of the school lunch in Japan. Linear mixed models were employed for evaluating the relationship between the characteristics of kids' meals and their fat (E%) or salt (g) content. Restaurant websites providing nutritional data of kids' meals in Japan. A total of 438 kids' meals offered by forty-two chain restaurant brands from across twenty food-service companies. Overall, 58·9, 40·6 and 34·5 % of the kids' meals were determined to be appropriate regarding their energy (≤2218 kJ), fat (≤30 E%) and salt content (<2 g). In addition, 15·5 % of kids' meals met the multiple standards of energy, fat and salt contents. 'Japanese-style' (restaurant-level characteristic) was associated with a decrease in the fat E% of kids' meals (β=-6·2; 95 % CI -11·0, -1·4) and an increase in the salt content (β=0·7; 95 % CI 0·06, 1·3). The characteristics of the restaurant-served kids' meals in Japan were high fat E% and high salt content from different cultural contexts of the Western and the Japanese diet.