Researchers have long focused on the accumulation of amyloid beta (Aβ) peptides in the brain as a primary pathological hallmark driving cognitive decline. This study investigated the neuroprotective effects of Rosa rugosa (RR) root extract and its key bioactive constituent, oleamide, against amyloid beta (Aβ)-induced neurotoxicity. Initially, an ethanolic extract of RR root was screened via in vitro assays to assess antioxidant and cytoprotective potential in rat pheochromocytoma cells. Subsequent fractionation, open-column chromatography, and preparatory thin-layer chromatography led to the isolation of oleamide, confirmed by gas chromatography–mass spectrometry and ¹H/¹³C nuclear magnetic resonance analyses. In vivo experiments using intracerebroventricularly injected Aβ in male mice demonstrated that both RR root extract and oleamide significantly improved cognitive performance in the Y-maze and passive avoidance tests. Additionally, oleamide restored acetylcholine levels and reduced malondialdehyde concentrations in brain tissue, indicating mitigation of oxidative stress and support of cholinergic function. No significant toxicity was observed, as evidenced by stable serum transaminase levels and unaltered body or brain weights. These findings highlight oleamide’s potential to protect against Aβ-driven pathology through multiple mechanisms, including reduced lipid peroxidation and improved neurotransmission. Further investigations into oleamide’s molecular targets and synergy with existing therapies may advance its development as a novel candidate for Alzheimer’s disease prevention or adjunct treatment.