Kotlin-class destroyers were Cold War era ships built for the Soviet Navy. The Russian name for this class was Project 56 Spokoiny (Спокойный, "tranquil"). 27 ships were built between 1955 and 1958; they were all decommissioned in the late 1980s. The Kildin class is based on the design of the Kotlins. The Chinese Luda class which is based on the Soviet Neustrashimy class, also borrows some design concepts from the Kotlin class.
This design was a smaller version of the Neustrashimy-class destroyer which was seen as being too large and expensive for economic series production, as well as too slow. Detailed design changes eliminated some of the problems seen during trials of Neustrashimy. A production run of 100 ships was planned but this was curtailed because of the advent of the guided missile. 32 were ordered, but four ships were completed as the Kildin class (Project 56E/EM). The last vessel was canceled.

科特林级56型“平静”（俄语：Спокойный）（英语：Kotlin-class）是苏联1953年至1958年量产的火炮鱼雷驱逐舰。1955年至1958年建造了27艘。到1980年代后期全部除役。北约以芬兰湾的科特林岛命名此型舰。

56型的建造，与美国同级的福里斯特·谢尔曼级驱逐舰同时进行，都是以130毫米舰炮、127毫米舰炮为主战武器。56型是苏联建造的最后一种火炮鱼雷驱逐舰。56型具有较好的适航性和高航速，动力充裕，因此成为以后改装为反潜、防空任务的平台。

基尔丁级驱逐舰是以56型为基础放大设计。中国的旅大级驱逐舰是借鉴了56型的部分图纸、技术资料，以及相关设备如TB-8蒸汽轮机的资料和实物样品，在此基础上进行研究改进而成。