Plant biostimulants are utilized in order to improve cabbage production and enhance qualitative characteristics while avoiding negative and harmful effects on human health because they are completely biodegradable, nontoxic, and do not pose a threat to humans. This study was executed during two winter seasons (2021/2022 and 2022/2023) to study the influence of plant biostimulants e.g. glycine, proline, seaweed extract, ascorbic acid and citric acid on growth, productivity, and head quality of cabbage cv. Brunswick. The results revealed that seaweed extract, glycine and ascorbic acid promoted vegetative growth traits i.e. number and weight of non-wrapped leaves and head weight in both seasons of the study. Moreover, seaweed extract surpassed glycine and ascorbic acid treatments for enhancement of vegetative traits.  Treated plants with seaweed extracts showed the highest mean values for yield traits such as plant weight, marketable and total yield. Additionally, glycine and ascorbic acid treatments showed relatively positive effects for yield traits in both seasons, while proline and citric acid insignificant effects. Regarding head traits, glycine treated plants exhibited the largest mean values for equatorial and polar diameters followed by the seaweed extract and ascorbic acid. Likewise, glycine resulted in the largest mean values of head volume followed by seaweed extracts and ascorbic treatments. Dry matter content increased with the application of seaweed extract and glycine, whereas glycine, seaweed extract and ascorbic showed positive effects for TSS in both seasons. Generally, the results reflected relatively high improvement in vegetative, yield and head traits by the exogenous application of plant biostimulants, namely seaweed extracts, glycine and ascorbic; with superiority of seaweed extracts for enhancing cabbage productivity and quality.