English glassmaker, a technical innovator who sparked a resurgence of British interest in classical Greek and Roman glassworking methods, particularly in the art of cameo glass.

Northwood studied art before serving as an apprentice in the large glass-manufacturing firm of W.H., B., and J. Richardson, at Wordsley (in the glassmaking district of Stourbridge). After working for a time in his brother's carpentry workshop, Northwood went to work for Benjamin Richardson (Richardson, Benjamin), a former partner in the firm, who had established his own glassmaking business. Richardson's admiration for ancient glass and his desire to produce comparable modern pieces inspired Northwood's ventures into new techniques for carving and etching glass. After studying the Elgin Marbles and the Portland Vase in the British Museum, Northwood began work on his Elgin Vase (1873), commissioned by the glass-factory owner Benjamin Stone. The two-handled urn—encircled by a frieze carved in relief and decorated with etched classical motifs—inspired many British glassworkers to similarly embellish their works, with the aid of a glass-etching machine developed by Northwood himself.

Northwood's major work, his Portland Vase (completed in 1876), was a copy of the Roman original made during the 1st century AD. Instead of using glass-etching tools to cut into the superimposed layers of coloured glass (an opaque white casing over a dark blue ground), Northwood worked by hand, with steel tools of his own design, to create the white-on-blue cameo figures. The piece took more than three years to complete, during which time Northwood repeatedly visited the British Museum to see and handle the original. Although Richardson had, many years earlier, offered £1,000 to any glassmaker who could produce a replica of the famous Roman vase, Northwood's masterpiece was commissioned by another local manufacturer, Philip Pargeter.

Northwood's Portland Vase was the first such successful reproduction in the original medium, and his accomplishment was celebrated by glassmakers throughout the world. The art of cameo glass, thus revived in England, was carried on by numerous craftsmen of note, including Northwood's nephew William (1858–1937) and his son, John Northwood II (1870–1960).