Biodegradable polymers are polymers that can be decomposed by the action of living organisms. Whereas most polymers are designed for longevity, biodegradable polymers are not. Biodegradable polymers can be derived from renewable raw materials, petrochemicals, or combinations thereof.

Polymers are the majority component of most plastics, so the discussions of biodegradable plastics and polymers are intimately related. While the words "bioplastic" and "biodegradable polymer" are similar, they are not synonymous. Not all bioplastics (plastics derived partly or entirely from biomass) are biodegradable, and some biodegradable plastics are fully petroleum based. As more companies are keen to be seen as having "green" credentials, solutions such as using bioplastics are being investigated and implemented more. The definition of bioplastics is still up for debate. The phrase is frequently used to refer to a wide range of diverse goods that may be biobased, biodegradable, or both. This could imply that polymers made from oil can be branded as "bioplastics" even if they have no biological components at all. However, there are many skeptics who believe that bioplastics will not solve problems as others expect.

Very early work on biodegradable materials necessarily preceded the era of synthetic polymers, which require petrochemicals. This early work focused on natural polymers or their derivatives. One of the first medicinal uses of a biodegradable polymer was the catgut suture, which dates back to at least 100 AD. The first catgut sutures were made from the intestines of sheep, but modern catgut sutures are made from purified collagen extracted from the small intestines of cattle, sheep, or goats.

In the 1830's, cellulose was converted to gun cotton (cellulose nitrate) and then cellulose acetates, which are probably the first biodegradable (semi-synthetic) polymers. Early studies on the biopolymers polyhydroxyalkanoate (PHA) provided the groundwork for its commercial production. Follow-up efforts by W.R. Grace & Co. (USA) failed. When OPEC halted oil exports to the US to boost global oil prices in 1973, efforts to produce PHB using the strain Alcaligenes latus by Imperial Chemical Industries (ICI UK) also collapsed. The specific PHA produced in this instance was a scl-PHA. Efforts continue. Related to PHA is polylactic acid (PLA). Studies on its polymerization of lactic acid and its derivatives began at DuPont in the 1930's. In the 1970's, a copoiymer of PLA and polyglycolic acid led to the commercialization of Vicryl, resorbable suturing material.

The concept of synthetic biodegradable plastics and polymers was first introduced in the 1980s. In 1992, an international meeting was called where leaders in biodegradable polymers met to discuss a definition, standard, and testing protocol for biodegradable polymers. Also, oversight organizations such as American Society for Testing of Materials (ASTM) and the International Standards Organization (ISO) were created.^{[citation needed]} Some clothing and grocery store chains have pushed to utilize biodegradable bags in the late 2010s.

Industrial production of biodegradable polymers commenced on scale in the late 1990's.

Most biodegradable polymers are polyesters. The ester group (RC(O)OR') is susceptible to hydrolysis by both chemical (i.e. simply exposure to water) and enzymatic action. In addition to polymers, the biodegradability of additives requires attention.

Biologically synthesized polymers are produced from natural origins, such as plants, animals, or micro-organisms.