Alpha by itself may refer to:

• The first letter of the Greek alphabet, Α α, which also has some cultural meanings; see alpha (letter).
• The letter A in the NATO phonetic alphabet, which is spelled Alfa for the benefit of native Portuguese and Spanish speakers.
• A male in police CB code. (Delta represents a female)
• DEC Alpha, a microprocessor from DEC.
• Alpha TV - a Greek terrestrial channel
• Alpha TV Gujarati - a Gujarati language channel in India.
• Alpha (computer) - a fictional computer in Mike Walker's radio play Alpha.
• Alpha (Investment) - A coefficient measuring the risk-adjusted performance, considering the risk due to the specific security, rather than the overall market.
• Cronbach's alpha - a statistical measure of reliability.
• Fine-structure constant - usually denoted (Alpha)
• Alpha is a name of the first Magic: The Gathering cards set.

The International Space Station has sometimes been referred to as 'Alpha'.

Alpha may also be used in:

• An adjective to indicate the first or most significant occurrence of something., as in these examples:
  • alpha female or male - the individual in the community to whom the others defer. Humans and their nearest species-relatives, the chimpanzees, show deference to the alpha of the community by ritualized gestures such as bowing, allowing the alpha to walk first in a procession, or standing aside when the alpha challenges.
  • alpha geek - a slang term based on the above, referring to any person considered pre-eminent amongst geeks, such as Linus Torvalds.
  • alpha version or alpha release - the first release of a computer program or other product, likely to be very unstable but useful for demonstrating internally and to select customers.
  • alpha <name of constellation> - Bayer designation of (typically) the brightest star in a constellation.
  • alpha channel - a transparency information layer to supplement the three RGB color layers to make the RGBA color space.
  • H-alpha, an emission line created by Hydrogen atoms.
• Alpha particles
• Alpha course, a course in Christianity
• Alpha squad, a Russian special unit
• Alpha waves recorded by electroencephalography
• Alpha, Michigan
• Alpha, Minnesota
• Alpha, New Jersey
• In electrical engineering and electronics, the Greek letter α is often used to refer to the ratio of DC collector current to DC emitter current of a bipolar junction transistor.
• In electrical engineering and electromagnetic theory, the Greek letter α is often used to refer to the attenuation constant of an electromagnetic wave propagating through a specific medium.