Geek rock is a subgenre of Alternative Rock which embodies a nerdy aesthetic musically and lyrically. The genre typically features strong Pop Rock melodies and hooks, often drawing directly from Power Pop with its punchy sound and distorted guitars; however, unlike most forms of alternative rock, synthesizers and drum machines are fairly common due to its heavy influence from New Wave. These, and other electronics, may be used alongside other unconventional Rock instrumentation like piano, brass, woodwinds, accordion, melodica, or toy instruments to create a quirky or kitschy atmosphere to match its kitchen-sink approach to songwriting and arrangements. Geek rock is typically lyrically dense and focuses on less conventional topics—pop culture, history, science fiction, fantasy, mythology—but may also approach Pop mainstays like love and relationships with a nerdy twist. Much geek rock is humourous but typically falls short of being Comedy Rock due to its focus on irony, wordplay, and oddball subject matter for its humour, but more overtly comedic crossovers exist particularly in the realm of Musical Parody.

The geek rock genre was pioneered in the late 1980s and early 1990s by They Might Be Giants, whose upbeat and quirky songs built on the more intellectual bent of 1980s college-radio rock and the twitchy, synthesizer-laden sound of bands like Devo. Their 1990 major label debut Flood has been noted as a watershed moment in geek rock. This geekier side of alternative rock was embraced in the mid-to-late 1990s by bands like Self, Fountains of Wayne, Barenaked Ladies, and Weezer-offshoot The Rentals. Nerf Herder were likely the first group to self identify with the "geek rock" term.

The rising popularity of the internet in the new millennium had a massive impact on geek rock, democratising the production and distribution of music. Newer geek rock groups took on more of an Indie Pop-inspired DIY bent, combining lo-fi bedroom instrument recordings with consumer-grade keyboards and lyrics that frequently referenced video games and internet culture along with the genre's typical esoterica. Artists like Logan Whitehurst & The Junior Science Club, Lemon Demon, and Tally Hall found success using Flash animations and early viral videos on YouTube, and Jonathan Coulton became well-known for his songs composed for the Portal video game series, most notably "Still Alive". Other innovations in the 2000s included the incorporation of Chiptune by bands like I Fight Dragons and the emergence of fandom-based scenes like "wizard rock", a movement of Harry Potter-themed Indie Rock that was spearheaded by Harry and the Potters. The geek rock scene was renewed in the late 2010s with the emergence of Needlejuice Records, a label focused around remastered reissues of classic geek rock albums as well as releasing music from newer artists.