Diet Rite is the brand name of a line of diet sodas distributed by the R.C. Cola company (now part of Dr. Pepper & Seven-Up, Inc., which in turn is part of Cadbury-Schweppes plc).

Diet-Rite Cola was the first commercial diet soda, introduced in 1958. Initially released as a dietetic product, in 1962 it was marketed to the general public as a healthful beverage. It was sweetened with cyclamate and saccharin.

In 1964, Diet-Rite Cola (along with RC Cola), became the first soft drink sold in an all-aluminum can.

In 1969, with a Food and Drug Administration ban on cyclamate pending in the United States, the beverage was reformulated to eliminate the sweetener.

In 1983, Diet-Rite cola was reformulated again to eliminate sodium, making it the first sodium-free diet soda. In 1987, with saccharin losing popularity with the public as a possible carcinogen, Diet-Rite was once again reformulated, this time replacing the saccharin with NutraSweet brand aspartame and eliminating caffeine. In the 1990s, several fruit-flavored varieties of Diet-Rite were also introduced.

In 2000, the line was reformulated yet again, this time to replace aspartame with Splenda brand sucralose and Sunett brand acesulfame potassium. In so doing, it became the first major diet soda in the United States to use neither aspartame nor saccharin as a sweetener. In 2002, some flavors were slightly adjusted and the brand name lost the hyphen, becoming Diet Rite.

The flavors of Diet Rite available in the United States are Black Cherry, Cola, Golden Peach, Kiwi Strawberry, Red Raspberry, Tangerine, and White Grape. In most areas, only a few of these flavors are available.