The Castner Gold Medal on Industrial Electrochemistry is an biennial award given by the Electrochemical Technology Group of Society of Chemical Industry (SCI) to an authority on applied electrochemistry or electrochemical engineering connected to industrial research.  The award is named in honor of Hamilton Castner, a pioneer in the field of industrial electrochemistry, who patented in 1892 the mercury cell for the chloralkali process. Castner was an early member of SCI.
The medal is presented in a public lecture, usually at the annual Electrochem conference, which is organised by the Royal Society of Chemistry (RSC) Electrochemistry Interest Group and the SCI Electrochemical Technology Group. When this is not possible, the medal presentation and lecture takes place at SCI's headquarters.
The medal's design was conceived by Humphrey Paget by commission of SCI. At least until 1958, the award was called Castner Gold Medal.