The Fender Stratocaster was first introduced in 1954 after Leo Fender incorporated the input of professional musicians and members of Fender's staff to design a complementary guitar to the company's already popular Telecaster model. Popular with guitarists in virtually every style of music, the Fender Stratocaster is one of the most common guitars in the world. The major defining features of the instrument are its trademarked unique headstock shape and the body shape. However, in the years since 1954, many guitar companies have released guitar models with Stratocaster-style bodies, so it may be difficult to distinguish a lookalike from the real deal.
Look at the writing on the guitar's headstock. Fender Stratocasters have the words "Fender" and "Stratocaster" written on the headstock as well as where it was built and the serial number.
Examine the shape of the headstock if the writing has worn away. All of the machine heads are on one side of a Fender Stratocaster headstock and the headstock itself is straight in line with the neck, not angled. The other side has a shape that is unique to Fender Stratocasters. A semicircular shape is cut out of the top of the headstock, and beneath that is a carved section of wood that juts out before being cut back in line with the neck. The size of the jutting out section may differ slightly for different era Stratocasters, but the basic shape is the same. If the guitar's headstock matches the Stratocaster shape, at the very least, the neck is a Stratocaster neck.
Examine the body shape of the guitar. Fender Stratocasters bodies are cut away on both sides of the neck, known as a double-cutaway body, and have rounded edges near the bottom of the guitar.
Other defining features for most Fender Stratocasters include the neck plate on the back of the guitar, which usually has a fancy "F" that signifies Fender engraved on it, and the pickup and knob configuration. The pickups on a Stratocaster usually are three single-coil pickups lined up in a row underneath the strings, with the bridge pickup angled slightly. Stratocasters usually have three knobs below the bridge pickup in row that roughly follow the angle of the bridge pickup, and above them is generally a five-way pickup selector.
Take a guitar to a guitar shop if unsure of its identity. Serial numbers also aid in identifying a Fender Strat. Fender's website features a list of serial numbers that specify when its guitars were manufactured.