Male reproductive toxicity is defined as the adverse effects of chemicals on the male reproductive system, which can lead to conditions such as infertility. This study investigates the protective potential of Nasturtium officinale hydroethanolic extract (N. officinale) against MSG-induced testicular toxicity in albino rats. Twenty male albino Wistar rats, ageing (8-10 weeks) and weighting (230-280 g), were randomly divided into four groups:( control, MSG (2g kg b.w. orally), MSG + 200 mg kg b.w. of N. officinale, and MSG + 400 mg kg b.w. of N. officinale) for six weeks. Spectroscopic analysis confirmed successful extraction of bioactive compounds including flavonoids and phenolic acids. MSG administration caused severe testosterone suppression (0.96 ± 0.452 ng mL) compared to control group rats (2.539 ± 1.474 ng mL), accompanied by dramatic Hsd17b3 gene downregulation and extensive histopathological damage including seminiferous tubule degeneration and Leydig cell dysfunction. N. officinale extract admiration demonstrated dose-dependent protective effects, with low-dose restoring testosterone levels (2.436 ± 0.626 ng mL) and high-dose achieving superior protection (3.624 ± 1.114 ng mL). Molecular analysis revealed significant Hsd17b3 upregulation in both plant extract groups when compared with MSG alone group, while histopathological examination showed remarkable tissue recovery with preserved spermatogenesis. These findings demonstrate that Nasturtium officinale extract provides dose-dependent protection against MSG-induced testicular damage by supporting testosterone production, enhancing Hsd17b3 gene expression, and preserving normal testicular tissue, indicating its potential as a natural therapeutic agent for male reproductive health.