摇滚乐是流行音乐的一种形式，通常由显著的人声伴以吉他、鼓和贝斯演出，很多形态的摇滚乐也使用键盘乐器，如风琴、钢琴、电子琴或合成器。其他乐器，比如萨克斯管、口琴、小提琴、笛、班卓琴、口风琴或定音鼓有时也被应用在摇滚乐之中。此外，不太出名的曼陀铃或锡塔琴等弦乐器也被使用过。摇滚乐经常有强劲的强拍，围绕电吉他，空心电吉他，以及木吉他展开。
摇滚乐源自于1940和1950年代的“rock and roll”运动及rockabilly，此二者是由布鲁斯音乐，乡村音乐及其他音乐形式演进而来。All Music Guide杂志认为，“最纯粹的摇滚乐形式有三个和弦层次，一段有力而连贯的背景节奏，及吸引人的旋律。早期摇滚乐师从颇多，主要是布鲁斯乐，R&B，乡村音乐；同时也被宗教福音，传统流行乐，爵士乐和民间音乐影响。所有的这些影响都汇集到一个简单的、基于布鲁斯的歌曲结构中，它节奏快，引人起舞，引人陶醉。”
在20世纪60年代晚期，摇滚乐与民间音乐的融合产生出民谣摇滚，与布鲁斯的融合产生了布鲁斯摇滚乐，还与爵士乐融合产生出融合爵士乐。在某个不确定的时期又产生了迷幻摇滚。在70年代，摇滚乐吸纳了来自灵魂乐，放克以及拉丁音乐的元素。与此同时，摇滚乐产生出许多下属类型，比如软性摇滚，重金属，硬摇滚，前卫摇滚及朋克摇滚。20世纪80年代产生的摇滚类型包括合成器流行乐，硬核朋克以及另类摇滚。在90年代，这些类型中又加入了油渍摇滚，英伦摇滚，独立摇滚和新金属。
专门演奏摇滚乐的艺人团体被称为摇滚乐队或摇滚乐手。大部分摇滚乐团包括吉他手，主唱，贝斯手和鼓手，组成一个四人阵容。部分乐队取消了这其中的一个或几个角色或者让主唱同时担负起演奏乐器的任务，由此成为一个二人或三人组合。另外的乐团会增补一个或两个节奏吉他手或者一个键盘手。在比较罕见的情况下，乐队会使用诸如小提琴或大提琴这样的弦乐器，或者萨克斯管，小号，长号这样的管乐器。
摇滚乐不仅唱出人们对爱情，美好生活的追求，还发泄出对现实世界的不满，涉及到战争与和平，民主与政治等方面。其种类、风格繁杂，从几个大的方面来看，现代摇滚的发展主要基于黑人音乐、地下文化、现代科技以及“后现代”浪潮，形成以“金属”、“朋克”、“歌德”、“迷幻”、“说唱”、“黑色氛围”为主要风格的非主流音乐。

Rock music is a genre of popular music that originated as "rock and roll" in the United States in the 1950s, and developed into a range of different styles in the 1960s and later, particularly in the United Kingdom and the United States. It has its roots in 1940s' and 1950s' rock and roll, itself heavily influenced by rhythm and blues and country music. Rock music also drew strongly on a number of other genres such as blues and folk, and incorporated influences from jazz, classical and other musical sources.
Musically, rock has centered on the electric guitar, usually as part of a rock group with bass guitar and drums. Typically, rock is song-based music usually with a 4/4 time signature utilizing a verse-chorus form, but the genre has become extremely diverse and common musical characteristics are difficult to define. Like pop music, lyrics often stress romantic love but also address a wide variety of other themes that are frequently social or political in emphasis. The dominance of rock by white, male musicians has been seen as one of the key factors shaping the themes explored in rock music. Rock places a higher degree of emphasis on musicianship, live performance, and an ideology of authenticity than pop music.
By the late 1960s, referred to as the "golden age" or "classic rock" period, a number of distinct rock music sub-genres had emerged, including hybrids like blues rock, folk rock, country rock, and jazz-rock fusion, many of which contributed to the development of psychedelic rock, which was influenced by the counter-cultural psychedelic scene. New genres that emerged from this scene included progressive rock, which extended the artistic elements; glam rock, which highlighted showmanship and visual style; and the diverse and enduring major sub-genre of heavy metal, which emphasized volume, power, and speed. In the second half of the 1970s, punk rock both intensified and reacted against some of these trends to produce a raw, energetic form of music characterized by overt political and social critiques. Punk was an influence into the 1980s on the subsequent development of other sub-genres, including new wave, post-punk and eventually the alternative rock movement. From the 1990s alternative rock began to dominate rock music and break through into the mainstream in the form of grunge, Britpop, and indie rock. Further fusion sub-genres have since emerged, including pop punk, rap rock, and rap metal, as well as conscious attempts to revisit rock's history, including the garage rock/post-punk and synthpop revivals at the beginning of the new millennium.
Rock music has also embodied and served as the vehicle for cultural and social movements, leading to major sub-cultures including mods and rockers in the UK and the hippie counterculture that spread out from San Francisco in the US in the 1960s. Similarly, 1970s punk culture spawned the visually distinctive goth and emo subcultures. Inheriting the folk tradition of the protest song, rock music has been associated with political activism as well as changes in social attitudes to race, sex and drug use, and is often seen as an expression of youth revolt against adult consumerism and conformity.