Several factors influence the productivity and final quality of tomato fruit. These include mineral nutrition and factors that interfere with the crop’s growing environment, such as plant shading. In order to maintain the productivity and quality of tomato fruit during the crop’s off-season in Rio Grande do Sul, the aim of this study was to assess the influence of nitrogen fertilization, shading and the interaction between the two factors on the agronomic performance of the tomato crop in a protected environment. The factors shading and N doses had an influence on the agronomic performance, productivity and fruit quality of tomatoes grown in a protected environment. In this experiment, the variables analyzed showed better responses when the plants were not shaded than when they were shaded. With regard to nitrogen, the application of the nutrient contributed to better plant growth and development, crop productivity and fruit quality up to a certain dose (150 kg ha-1 in the unshaded environment and 225 kg ha-1 in the shaded environment).