Rosemary oil (Rosmarinus officinalis L.) is a potential therapeutic agent to treat Alzheimer's disease (AD), characterized by cognitive decline and memory impairment. We reviewed the effects of rosemary oil on cognitive functions in individuals with Alzheimer's disease, foccusing on its bioactive compounds, particularly 1,8-cineole, which has neuroprotective and cognitive-enhancing properties. Preclinical studies have shown that rosemary oil improves memory and reduces cognitive deficits in animal models of Alzheimer's through acetylcholinesterase inhibition, antioxidant activity and modulation of neuroinflammation. Clinical studies further, showed that aromatherapy with rosemary oil enhances the cognitive function and sleep quality in elderly populations. This review aimed to synthesize current research on the efficacy of rosemary oil in managing Alzheimer's disease, its potential as a complementary therapy along with traditional pharmacological treatment. The findings showed that rosemary oil improves quality of life of Alzheimer's disease patients.