The iMac G3 was the first model of the iMac line of personal computers made by Apple Inc. (formerly Apple Computer, Inc.), and the originator of the Legacy-free PC market category. Like the first Macs, the iMac G3 is an all-in-one personal computer, encompassing both the monitor and the system unit in a single enclosure.

Originally released in Bondi blue and later a range of other brightly colored, translucent plastic casings, the iMac shipped with a keyboard and mouse in matching tints.

In Walter Isaacson's biography of Steve Jobs, Jobs said "It looks so good you kinda' wanna lick it".

Steve Jobs reduced the company's large and confusing product lines immediately after becoming Apple's interim CEO in 1997^{[citation needed]}; toward the end of the year, Apple trimmed its line of desktop Macs down to the beige Power Macintosh G3 series, which included the iMac's immediate predecessor, the G3 All-In-One, which featured nearly identical specifications and was sold only to the educational market. Having discontinued the consumer-targeted Performa series, Apple needed a replacement for the Performa's price point. The company announced the iMac on May 6, 1998 and began shipping the iMac G3 on August 15, 1998.

The iMac is a range of all-in-one Macintosh desktop computers designed and built by Apple Inc.. It has been the primary part of Apple's consumer desktop offerings since its introduction in 1998, and has evolved through five distinct forms.

In its original form, the iMac G3 had a gum-drop or egg-shaped look, with a CRT monitor, mainly enclosed by a colored, translucent plastic case, which was refreshed early on with a sleeker design notable for its slot-loaded optical drive. The second major revision, the iMac G4, moved the design to a hemispherical base containing all the main components and an LCD monitor on a freely moving arm attached to it. The third/fourth major revision, the iMac G5 and the Intel iMac placed all the components immediately behind the display, creating a slim unified design that tilts only up and down on a simple metal base. The current iMac shares the same form as the previous model, but is thinner and uses anodized aluminum and a glass panel over the entire front. It also adds an SDXC slot directly under the slot-loading SuperDrive. The newest version features quad-core Intel processors across the line, 1 (on 21.5″) or 2 (on 27″) Thunderbolt ports, and a FaceTime HD camera, features introduced on the early 2011 MacBook Pro updates.