Developed from the earlier Su-9/11 series, the Sukhoi Su-15 'Flagon' was a high performance all-weather interceptor which was considerably more capable than its predecessors and went on to serve for the remainder of the Cold War. It shared the Su-11's general design but most noticeably differed by having side mounted intakes for its more powerful Tumansky engines. This allowed for a solid nose which housed a Taifun radar which was continually improved. The fuselage was also lengthened and was constructed primarily of aluminum, with some steel and titanium parts. The larger size allowed for three fuselage fuel tanks (plus wing tanks) which helped address one of the Su-9/11's main deficiencies: range. No gun armament was installed either, though gun pods could be fitted in later variants, which also had some ground attack capability. Like most advanced Soviet interceptors, the Su-11 was never exported, serving exclusively with air defense units. However, the limited look-down/shoot-down capability of the Taifun radar made it useless against low-flying aircraft and cruise missiles, and as a result, the Su-15 was used primarily against high-flying targets leaving the more difficult threats to the MiG-23P and MiG-25. Though it did not see combat, the Su-15 was involved in one of the most notorious Cold War incidents when one such aircraft shot down a Korean Air Lines 747 airliner that had strayed into Soviet airspace north-west of Japan, where it was confused with a US RC-135 intelligence-gathering aircraft. A small number of Su-15s remained in service until retired in the 1990s.

Maiden flight of the T-58 prototype took place tok place on 30 May 1962 and was followed by the pre-production Su-15 'Flagon-A' with Oryol-D radar which was inherited from the Su-11. Handling issues resulted in the Su-15 'Flagon-D' which had a revised wing design. The introduction of the Taifun radar resulted in the Su-15T 'Flagon-E' which was succeeded by the major production Su-15TM 'Flagon-F' with increased span wings, additional pylons, and improved engines and radar. The Su-15bis 'Flagon-G' was the ultimate development of this aircraft and had a resdesigned radome and a new powerplant but was never put into mass production due to engine shortages. Two-seat, radar-less trainer variants were known as the Su-15UT 'Flagon-C' and Su-15UM 'Flagon-G', the later based on the Su-15TM. Finally, the experimental Tu-15VD 'Flagon-B' was a V/STOL technology demonstrator with fuselage lift engines.