Kappa (Κ or κ) is the tenth letter of the Greek alphabet.

Kappa may also refer to:

• Cohen's kappa, also known as Kappa statistic
• Fleiss' kappa, another measure of inter-annotator agreement
• Kappa number, a measure of lignin content in wood pulp

• Kappa architecture, a purely streaming architecture, as opposed to lambda which uses the same architecture for batch and streaming

• Kappa (brand), an Italian sportswear brand
• Kappa Publishing Group, publishing company

• GM Kappa platform, subcompact rear-wheel drive automobile platform
• Lancia Kappa, an executive car
• Hyundai Kappa engine, automobile engine series

• Kappa, Illinois, a village
• Kappa Island, Antarctic island

• Kappa (folklore), a Japanese turtle-like humanoid
• Kappa (novella), by Ryūnosuke Akutagawa
• Kappa (Dungeons & Dragons), a game creature
• Death Kappa, a Japanese kaiju film
• Kappa (rocket), a family of Japanese sounding rockets
• Kappa TV, a TV channel based in Kerala
• Knowledge and Power Preparatory Academy IV or KAPPA IV, a middle school in the Bronx, New York City
• "Kappa", a 1999 song by Mogwai from the album Come On Die Young
• Kappa chain, a type of immunoglobulin light chain, part of the human immune system
• Kappa, one of the most popular emotes on live streaming platform Twitch
• Kappa effect, a sensory illusion relating to the human perception of time
• SARS-CoV-2 Kappa variant, one of the variants of SARS-CoV-2, the virus that causes COVID-19

• Honda Capa, a car sold in Japan
• Kalpa (aeon)
• Kapa (disambiguation)
• κ-opioid receptor
• Kappaphycus alvarezii, a type of seaweed
• All pages with titles beginning with Kappa