Extreme or Extremes may refer to:

• Extreme (band), an American band, mostly known for its ballad "More than Words"
• Extreme weather, severe or unseasonal weather
• Extreme value, the largest and the smallest element of a set
• Extremism, ideas or actions beyond what is deemed acceptable
• Extreme sport, featuring speed, height, danger or spectacular stunts
• Extremophile, an organism which thrives in or requires "extreme" conditions
• Extreme Associates, a pornographic video and DVD company
• Extreme Programming, also known as XP
• Extreme (marketing), the term as used in advertising and marketing
• Dance Dance Revolution EXTREME, a music video game produced by Konami
• Extreme Championship Wrestling, the former independent promotion that now operates as a brand for World Wrestling Entertainment
• Extreme Paintbrawl, a budget first person shooter that is considered one of the worst games ever
• Extreme, an autobiography by Sharon Osbourne
• Extreme Networks, a California based enterprise level networking hardware company
• Extreme Sports Channel, a Netherlands-based extreme sports television channel available across Europe and the Middle East
• Extreme Records, a record label
• Extremes, a television series
• Extremes (album), a 1994 album by Collin Raye

X-Treme may refer to:

• Adam X the X-Treme, a Marvel Comics character also known as Adam X or Adam Neramani
• Agostino Carollo, an Italian singer, disc jockey, and producer, better known as "X-Treme"

Xtreme or XTREME may refer to:

• Xtreme Beverages, a manufacturer of 100% fruit juices, smoothies, teas and water
• Xtreme Pro Wrestling
• Xtreme (group), a Latin music group
• XTREME Technologies GmbH, a research corporation between Jenoptik and Ushio for doing EUV lithography research using funds from Intel