Iris Associates was a software development company founded in Littleton, Massachusetts on December 7, 1984 by Ray Ozzie to build the software ultimately known as Lotus Notes. Tim Halvorsen and Len Kawell, who joined Iris shortly in January of 1985, met Ray Ozzie years before while all were working on the University of Illinois PLATO project. They are widely regarded as the core team behind the creation of Lotus Notes.

The company's primary funding came from a contractual relationship with Lotus Development Corp., best known at the time for its Lotus 1-2-3 spreadsheet software. Lotus funded development of Iris' product (then code-named simply "Notes") in exchange for a future option to purchase exclusive intellectual property, marketing, and sales rights. After this option was ultimately exercised years later by Lotus, Iris was additionally compensated through royalties on gross product sales. Lotus Notes was brought to market on Iris' 5th anniversary, December 7, 1989.

The author/publisher contractual relationship between Iris Associates and Lotus Development continued until 1984, when Iris was purchased by Lotus for approximately US$84 million.

Only a year later, in the face of an apparent rapid decline of its desktop business, Lotus itself was purchased by IBM for approximately US$3.5B. Approximately US$3B of this price is generally attributed to the purchase of the Notes business.

At the time of the IBM purchase, Lotus reported that Notes had approximately 2.2M users. In 2004, nearing the 20th anniversary of the founding of Iris Associates, IBM reported that Notes has over 110M users.