Castor oil is, as many other plant oils, a very valuable renewable resource for the chemical industry. This review article provides an overview on this specialty oil, covering its production and properties. More importantly, the preparation, properties and major application possibilities of chemical derivatives of castor oil are highlighted. Our discussion focuses on application possibilities of castor oil and its derivatives for the synthesis of renewable monomers and polymers. An overview of recent developments in this field is provided and selected examples are discussed in detail, including the preparation and characterization of castor oil-derived polyurethanes, polyesters and polyamides.