The Shields class is a class of keelboat devised in 1963 by US sailor Cornelius Shields, one of the foremost proponents of one-design sailing in the US. He conceived of a modern followup to the International One Design (IOD). The new boat would have the balance and beauty of the IOD while incorporating modern trends such as fiberglass construction. Shields commissioned Olin Stephens of Sparkman and Stephens for the design. The boat was intended for use by the yacht clubs around the Long Island Sound near New York, for racing and training.
The first batch of 20 boats were built at the Cape Cod Shipyard, and donated to training schools on the US east coast. In total over 100 boats were donated to colleges across the US. Over 250 have been built and many are actively raced in fleets around the US.
Its principal dimensions are:
- Length overall: 30 ft 2 in (9.19 m)
- Waterline length: 20 ft (6.1 m)
- Beam: 6 ft 5 in (1.96 m)
- Draft: 4 ft 9 in (1.45 m)
- Displacement: 4,600 lb (2,100 kg)
- Ballast: 3,080 lb (1,400 kg)
- Sail area (main, jib) 360 sq ft (33 m2)
- Sail area (spinnaker) 520 sq ft (48 m2)
In the USA, the Shields enjoys a strong National Association that organizes annual championship regattas.
Shields Class National championships have been contested since 1965. Past winners are listed on the Shields class website. 
- "Shields 30". School of Sailing and Seamanship, Orange Coast College. Retrieved 2018-09-24.
- "CLASS RULES - "Blue Book"". Shields Class Sailing Association. April 2017. Retrieved 2018-09-24.
- "Shields Class Sailing Association Fleets". Shields Class Sailing Association. Retrieved 2018-09-24.
- "Shields National Championship Trophy Winners". Shields Class Sailing Association. Retrieved 2018-09-24.