Sagittarius is the ninth astrological sign in the Zodiac, originating from the constellation of Sagittarius. In western astrology, the sign is now no longer aligned with the constellation as a result of the precession of the equinoxes. Sagittarius is considered a "masculine," positive (extrovert) sign. It is also considered a fire sign and one of the four mutable signs. Sagittarius is ruled by the planet Jupiter. Being the ninth sign of the zodiac, Sagittarius has been associated with having the astrological ninth house.

Individuals born when the sun was in this sign are considered Sagittarius individuals. Under the tropical zodiac, the sun enters Sagittarius on November 22 and exits by definition at the moment of winter solstice on December 21. Under the sidereal zodiac, it is currently there roughly from December 16 to January 14. The Sanskrit name of Sagittarius in Hindu astrology is Dhanu.

Generally, Sagittarius is considered compatible with same element signs, Aries, Leo and Sagittarius itself. These signs share a fiery demeanor and are believed to relate with each other on that merit.

There are many variables that determine compatibility in astrology, such as birth dates, birth months, birth years, position of a sign within the Sun, the Moon, Stars, etc. The signs listed as compatible with Sagittarius do not reflect an individual profile or individual reading as interpreted within astrology, but rather reflect a general guideline and reference to compatibility as dictated by variables such as Qualities and Elements within the Zodiac. The branch of astrology dealing with non-interpersonal compatibilities is called Synastry.