Castor oil extracted from the castor oil seeds of Ricinus communis is an important naturally occurring oil identified as a useful raw material for diverse industrial applications. Historically, the oil has been used in medicinal fields (as a laxative agent) as well as in cosmetics. The main attractive attributes of this oil include biodegradability and non-volatility. Thus, this has recently enabled derivatization to afford value-added chemicals through alternative green synthetic protocols. The oil contains a large percentage of an unusual fatty acid, 12-hydroxy-9-cisoctadecenoic acid, commonly known as ricinoleic acid. Ricinoleic acid can be easily extracted through chemical processes and subsequently exploited as a biosource for the production of high-grade lubricants, transparent typewriter and printing inks, textile dyes, leather preservation agents and polyamide nylon-type fibres. The most recent advances identify castor oil and its major isolate (ricinoleic acid) as potential green solvents and/or capping agents in the synthesis of high quality nanomaterials and nanocomposites.