Symphonic metal is a cross-genre style designation for the symphonic subsets of heavy metal music subgenres. It is used to denote any metal band that makes use of symphonic or orchestral elements. The style features the heavy drums and guitars of metal with different elements of orchestral classical music, such as symphonic instruments, choirs and sometimes a full orchestra, or just keyboard orchestration.

Symphonic metal bands can feature classically trained vocalists, in which case they can be attributed nicknames such as opera metal or operatic metal. Perhaps the most prominent examples of symphonic metal bands are Swedish band Therion, Finnish band Nightwish, German band Xandria, Italian band Rhapsody of Fire, American bands Lorna Shore and Trans-Siberian Orchestra and Dutch bands Epica and Within Temptation. Those bands place a large focus on elements prevalent in film scores in addition to the more basic classical components utilized more widely in the genre. Many people who participate in this genre of metal music have a degree in musical thought or have been taught how to sing in a classical style.

The metal subgenres most typically featuring a subset of symphonic bands are gothic metal, power metal, black metal, death metal and classic heavy metal. As with many other metal bands, those adopting a symphonic style may feature influences from several metal subgenres.

Music workstation keyboards and orchestras are often a key feature of the style, distinguishing symphonic from non-symphonic bands within the same metal subgenre. Other instruments, including guitars, bass and drums, may at times play relatively simple parts in contrast to the complex and nuanced keyboard and/or orchestral parts. Bands that do not use live orchestral instrumentation on their recordings or when playing live typically utilize factory presets on workstation keyboards (i. e., strings, choirs, pianos, pipe organs, etc.) to conjure up a "pseudo-orchestral" sound, where parts are played idiomatically according to keyboard technique. This is particularly characteristic of lesser-known bands on tighter budgets. Some symphonic metal bands abstain from using keyboards entirely, preferring to use orchestral backing tracks pre-recorded by a live symphony orchestra and/or choir during an album session, or recorded using virtual software instruments in a sequencer. This is particularly characteristic of bands that feature deeper and more complex arrangements which could be more difficult for one or two keyboardists to reproduce faithfully in a live performance.

It is more difficult to generalize about the role of the classic metal instruments (guitars, bass and drums), as they vary depending on the metal subgenre to which the symphonic band mostly associates. With varying frequency, symphonic bands may employ these instruments (as well as the lead vocals) to play more simple, catchy melodies than non-symphonic bands, which arguably make the symphonic metal style one of the most accessible in metal.

Songs are often highly atmospheric, though more upbeat than those of many non-symphonic metal bands; songs with morbid themes routinely feature prominent major-key fanfares. Particularly central to creating mood and atmosphere is the choice of keyboard timbre.

Lyrics cover a broad range of topics. As with two of its often overlapping elements, power metal and opera (including symphonic progressive rock), fantasy and mythological themes are common. Concept albums styled after operas or epic poems are not uncommon.

Bands in this genre may often feature a female lead vocalist, usually a soprano. Male vocalists (baritone or bass-baritone), are also common in gothic metal. Growling, death-metal-style vocals are not unknown but tend to be used less frequently than in other metal subgenres (a notable exception being Mark Jansen in Epica). Backing vocals, often consisting of a choral ensemble or full choir, may be employed.