Gender in Spanish

Gender is one of the most difficult aspects of Spanish grammar for beginners. It is not so difficult when talking about people, since grammatical gender - masculine or feminine - usually (but not always) matches up with a person's gender - male or female. But every noun in Spanish has a gender assigned to it - and it you can't make guesses based on the "masculinity" or "femininity" of the item. For example, el vestido [dress] is masculine, and la corbata [necktie] is feminine. Part of learning a new Spanish noun means learning the gender of that noun. This is especially important because adjectives and pronouns agree in gender with the noun they modify or replace. Luckily, there are some patterns that can help you guess the gender of a noun that might be unfamiliar.

Feminine Nouns
Nouns referring to women are feminine
La abuela [the grandmother]
La profesora [the teacher]

Nouns ending in -a are typically feminine.
Examples:
La manzana [the apple]
La película [the film]
Las gafas [the eyeglasses]

Nouns ending in -dad, -tad, and -tud are typically feminine.
Examples:
La Universidad [the university]
La Amistad [friendship]
La juventud [youth]

Nouns ending in -ción, -sión, and -gión are typically feminine.
Examples:
La estación [the season]
La televisión [the television]
La región [the region]

Nouns ending in -triz are feminine.
Examples:
La actriz [the actress]
La directriz [the director {female}]

Nouns ending in -umbre are feminine.
Example:
La contumbre [the custom]

Letters are feminine.
Example:
La z [Z]

Shortened versions of feminine nouns remain feminine (this is an area of common mistakes, since these words "look" masculine)
Example:
La foto (la fotographia) [the photograph]
La moto (le motocicleta) [The motorcycle]

Masculine Nouns
Most nouns that do not fit the above categories are masculine, in addition to the following categories:

Nouns ending in an accented vowel are usually masculine.
Examples:
El rubí [the ruby]
El tabú [the taboo]

Nouns ending in -aje, -ambre, and -or are usually masculine.
Examples:
El mensaje [the message]
El calor [heat]
El hambre [the hunger]

Infinitives used as nouns are masculine.
Examples:
El hablar [talking]
El bailar [dancing]

Months, days of the week, and numbers are masculine.
Examples:
El agosto [August]
El lunes [Monday]
El 5 [five]

Words of Greek origin ending in -ma, -ta, or -pa
Examples:
El programa [the program]
El planeta [ the planet]
El mapa [ the map]

Some common exceptions:
El día [the day]
El sofá [the sofa]

Feminine Nouns that take the article 'el'
Careful! If a feminine noun starts with a stresses a- or ha-, it will take the definite article "el." It remains feminine for purposes of gender agreement; this change occurs to avoid the choppiness of "la a-"
Examples:
El agua / las aguas [the water, the waters]
El habla / las hablas [the speech / the speeches]