Mr. Machine is a once popular children's mechanical toy originally manufactured by the Ideal Toy Company in 1960. It was a robot-like creation in the shape of a man wearing a top hat, fixed in a permanent grin.

The head was attached to a mechanical body with a giant windup key at the back. When the toy was wound up it would "walk", repeatedly ring a bell mounted on its front and after every few steps emit a mechanical "Ah!", as if it were speaking. The toy stood about 18 inches (roughly 46 cm).

The gimmick of Mr. Machine was that one could not only see all its mechanical parts, but also take the toy apart and put it back together easily, like a Lego toy or a jigsaw puzzle.

Mr. Machine was one of Ideal's most popular toys. The company brought it back in 1978, but with some alterations: it could no longer be taken apart (owing to the tendency of very young children to put small pieces in their mouths which could be accidentally swallowed or present a choking hazard), and instead of ringing a bell and making the "Ah" sound, it now whistled "This Old Man".

This later version of Mr. Machine was brought back once more in the 1980s. In 2004, the Poof-Slinky Company remanufactured the original 1960 version (using the actual Ideal molds whenever possible) which made the original sounds and could be disassembled, but with the intention of being marketed to nostalgic adults as a collectable.