Cultivation of sugar beet in the tropical and subtropical regions is rapidly growing as an important component of the sugar industry. The present study was carried out at the Agricultural Research Farm of the Delta Sugar Company, El-Hamoul, Kafr El-Sheikh, north of Egypt, in two growing seasons 2019/2020 and 2020/2021 to determine the effect of the foliar application of algae extract as a source of bio-stimulator and inter-row planting distances on the yield and quality of four sugar beet varieties. The results revealed that decreasing the inter-row planting distance (50 cm) accompanied with foliar application of algae extract has significantly promoted sucrose content, Na content, quality index%, root yield, recoverable sugar%, recoverable sugar yield and sugar loss yield, and reduced K%, α-amino-N% and sugar loss%. The multigerm variety Husam produced the highest values of sucrose content (20.17%), Na content (1.63%), quality index (82.50%), and recoverable sugar (17.86%) with sprayed of algae extracts compared to the control. Meanwhile, foliar application of algae extract to the monogerm variety Garrot produced the highest root yield (48.55 t feddan-1; Feddan = 4200 m2), recoverable sugar yield (7.71 t fed-1) and sugar loss yield (1.16 t fed-1). In general, planting sugar beet at 50 cm inter-row distances with foliar application of algae extract resulted in the highest values of sucrose content, Na content, quality index %, root yield, recoverable sugar %, recoverable sugar yield, and sugar loss yield, and the lowest values of K%, α -amino-N%, and sugar loss%.