Recently, phytochemicals in plants have evoked interest as sources of naturally beneficial substances and as alternatives to antimicrobials. Based on these benefits, it was hypothesized that garden cress (GC; Lepidium sativum) supplementation could overcome the negative impacts of severe heat stress on the reproductive and lactation performance, physiological parameters, and antioxidant status of rabbits. Twenty-four mature V-line does (6 months old) with an average body weight of 3.65 ± 0.54 kg were randomly assigned into four homogenously equal groups (n = 6) according to the level of supplemented GC seeds. Rabbits in the control group were fed a basal diet without GC seeds (GC 0), the other three treatment groups (GC 3, GC 4.5, and GC 6) were fed a basal diet supplemented with GC seeds at levels 3, 4.5 and 6%, respectively. Investigations revealed that the inclusion of 3% GC enhanced the litter weight of heat-stressed rabbits on the 7th, 14th, and 21st days. Furthermore, treatment with 3% and 6% GC seeds increased the milk yield on the 28th day. the most of lipid profile parameters, such as cholesterol, triglyceride, high-density lipoprotein (HDL), low-density lipoprotein (LDL), serum urea levels, and antioxidant status improved in rabbits supplemented with 6% GC. In conclusion, the dietary supplemention of GC seed at 6% increased milk yield at 28th day “weaning age”, consequently, improved the blood lipid profile and antioxidant status. Further studies should be conducted to commercialize theusage of garden cress seeds as a supplement in rabbits.