The Connection Machine was a series of supercomputers that grew out of Danny Hillis's research in the early 1980s at MIT on alternatives to the traditional von Neumann architecture of computation. The CM-1, developed at MIT, was a "massively parallel" hypercube arrangement of thousands of very simple processors, each with their own RAM.

Hillis and Sheryl Handler founded Thinking Machines in Waltham, Massachusetts and assembled a team to develop the CM-2, which depending on the configuration had as many as 65,536 processors. A later modification added numeric co-processors to the system, with some fixed number of the original simple processors sharing each numeric processor.

With the CM-5, Thinking Machines switched from the CM-2's hypercube architecture of simple processors to a fat tree network of RISC processors (Sun SPARCs).

The full list of Connection Machine models, in order of when they were introduced, are CM-1, CM-2, CM-200, CM-5, CM-5E.