Abstract The objective of this study was to evaluate the foliar application of the biostimulant QuitoMax at concentrations 100, 200, 300 and 400 mg·ha−1 in comparison to a control without the application of QuitoMax on the height and stem thickness of tomato plants. The durations of the plant phenological phases, productive indicators (the number of fruit, bunches per plant, the number of fruits per bunches, the polar and equatorial diameters of the fruit, the mass of the fruit and crop yield), the quality of the fruit expressed as the total soluble solids and acidity, and the commercial quality of the harvested fruits were also evaluated. The highest concentrations of QuitoMax (300 and 400 mg·ha−1) were found to produce the most vigorous plants, lengthened the duration of the plant phenophases, and resulted in significantly higher values in the production indicators, including the fresh mass of the fruits and performance. Additionally, they produced fruits with a higher content of total soluble solids.