Objective: The objective of this study was to evaluate the change in energy and nutrient content of menu items sold in large UK chain restaurants (e.g., fast-food, full-service) from 2018 to 2020. Design: Observational study Setting: Energy and nutritional information of menu items served by 29 large UK chain restaurants that consistently provided this information online in all three years. Data were collected in 2018 (March – April), 2019 (April), and 2020 (October – November) from restaurant websites. Primary and secondary outcome measures: The per-item energy and nutrient (saturated fat, sugar, and salt) changes in all items available on menus (“all menu items”) and recurring items that were consistently available on menus in all three years (“core menu items”). Results: Our study included 7,770, 9,213, and 6,928 menu items from 29 chain restaurants in 2018, 2019, and 2020, respectively. Our results showed that sugar content declined from 2018 to 2020 among all menu items (per-item: -0.43g/year, 95%CI= -0.66, -0.21). This reduction in sugar was evident in beverages, sandwiches and desserts. Among core menu items (N=1,855), sugar content reduced significantly from 2018 to 2020 (per-item: -0.31g/year, 95%CI= -0.45, -0.17), especially in beverages. Energy, salt, and saturated fat content in menu items remained constant overall, in both all menu items and core menu items. Fewer food categories had significant changes in sugar, salt, and saturated fat content among core menu items, compared to all menu items. Conclusions: From 2018 to 2020, sugar content declined in restaurant menu items, which may reflect a response to the Sugar Reduction Strategy and the effects of the Soft Drinks Industry Levy. In contrast, there was little change in other nutrients. Future policies addressing the overall nutritional quality of restaurant foods, rather than single nutrients, may help the restaurant sector move towards offering healthier foods.