Ricinus communis (Euphorbiaceae), commonly known as the castor oil plant, is prized for its versatile applications in medicine, industry, and agriculture. It features large, deeply lobed leaves with vibrant colours, robust stems with anthocyanin pigments, and extensive root systems for nutrient absorption. Its terminal panicle-like inflorescences bear monoecious flowers, and its seeds are enclosed in prickly capsules. Throughout its various parts, R. communis harbours a diverse array of bioactive compounds. Leaves contain tannins, which exhibit astringent and antimicrobial properties, and alkaloids like ricinine, known for anti-inflammatory properties, as well as flavonoids like rutin, offering antioxidant and antibacterial properties. Roots contain ellagitannins, lupeol, and indole-3-acetic acid, known for anti-inflammatory and liver-protective effects. Seeds are renowned for ricin, ricinine, and phenolic compounds crucial for industrial applications such as biodegradable polymers. Pharmacologically, it demonstrates antioxidant effects from flavonoids and tannins, confirmed through minimum inhibitory concentration (MIC) assays for antibacterial activity. It shows potential in managing diabetes via insulin signalling pathways and exhibits anti-inflammatory properties by activating nuclear factor erythroid 2-related factor 2 (Nrf2). Additionally, it has anti-fertility effects and potential anticancer activity against cancer stem cells. This review aims to summarize Ricinus communis’s botanical properties, therapeutic uses, chemical composition, pharmacological effects, and industrial applications. Integrating the current knowledge offers insights into future research directions, emphasizing the plant’s diverse roles in agriculture, medicine, and industry.