The Tinkertoy Construction Set is a construction set toy for children. It was designed in 1914—six years after the Frank Hornby's Meccano sets—by Charles H. Pajeau, who formed the Toy Tinker Company in Evanston, Illinois to manufacture them. Pajeau, a stonemason, designed the toy after seeing children play with sticks and empty spools of thread. Pajeau partnered with Robert Pettit and Gordon Tinker to market a toy that would allow and inspire children to use their imaginations. After an initially-slow start, over a million were sold.

The cornerstone of the set is a wooden spool roughly two inches (5 cm) in diameter, with holes drilled every 45 degrees around the perimeter and one through the center. Unlike the center, the perimeter holes do not go all the way through. With the differing-length sticks, the set was intended to be based on the Pythagorean progressive right triangle.

The sets were introduced to the public through displays in and around Chicago which included model Ferris wheels. Tinkertoys have been used to construct complex machines, including Danny Hillis's tic-tac-toe-playing computer (now in the collection of the Computer History Museum in Mountain View, California) and a robot at Cornell University in 1998.

One of Tinkertoy’s distinctive features is the toy’s packaging. Initially, the mailing tube design was chosen to reduce shipping costs. Early versions of the packaging included an address label on the tube with space for postage. To assist buyers in differentiating between the various offerings, sets were placed in mail tube packages of different sizes and also delineated with a number (e.g.: 116, 136) and a name (e.g.: major, prep, big boy, junior, grad). A colorful "how-to" instruction guide accompanied each set. In the 1950s, color was added and the wooden sticks appeared in red, green, blue, and peach.

The main manufacturing location was a 65,000-square-foot four-story plant at 2012 Ridge Avenue, Evanston, Illinois.

Tinkertoys were inducted into the National Toy Hall of Fame at The Strong in Rochester, New York, in 1998.

Hasbro bought the Tinkertoy brand and currently produces both Tinkertoy Plastic and Tinkertoy Classic (wood) sets and parts. The US rights are now owned by Basic Fun!.