Beryllium copper, also known as copper beryllium, BeCu or beryllium bronze, is a metal alloy of copper and 0.5 to 3% beryllium, and sometimes with other alloying elements, and has significant metalworking and operating performance qualities.

Beryllium copper is a ductile, weldable, and machinable alloy. It is resistant to non-oxidizing acids (for example, hydrochloric acid, or carbonic acid), to plastic decomposition products, to abrasive wear and to galling. Furthermore, it can be heat-treated to improve its strength, durability, and electrical conductivity. Beryllium copper attains the highest strength of any copper-based alloy.

As beryllium compounds are toxic there are some safety concerns for handling its alloys. In solid form and as finished parts, beryllium copper presents no particular health hazard. However, breathing its dust, as formed when machining or welding may cause serious lung damage. Beryllium compounds are known human carcinogens when inhaled. As a result, beryllium copper is sometimes replaced by safer copper alloys such as Cu-Ni-Sn bronze.

Beryllium copper is a non-ferrous alloy used in springs, spring wire, load cells and other parts that must retain their shapes during periods in which they are subjected to repeated stress and strain. Due to its electrical conductivity, it is used in low-current contacts for batteries and electrical connectors.

Because Beryllium copper is non-sparking but physically tough and nonmagnetic, it is used to make tools that can safely be used in environments where there are explosive vapors and gases e.g. oil rigs. Various tool types are available e.g. screwdrivers, pliers, spanners, cold chisels and hammers.

Another metal sometimes used for non-sparking tools is aluminum bronze. Compared to tools made of steel, beryllium copper tools are more expensive, not as strong and wear out more quickly. However, the advantages of using beryllium copper in hazardous environments outweigh these disadvantages.