If you’re learning Spanish, one of the very first hurdles you’ll encounter is this: every noun has a gender. Not just people, not just animals — things, ideas, concepts too: el coche, la casa, el problema, la gente. And then there’s the plural, which seems straightforward but has a few twists.
The rules governing gender and number in Spanish are more systematic than they might appear: once you grasp the underlying logic, you’ll recognise a word’s gender almost instinctively, and everything that depends on it — articles, adjectives, agreement — will fall into place naturally.
In this article, you’ll find a clear, structured explanation with plenty of examples, so you can start using Spanish nouns with confidence.
1. Masculine and feminine: the basic rules
In Spanish, almost all nouns are either masculine or feminine. There is no neuter gender as in German or Latin. The first step is learning to recognise gender by looking at the ending of a word — its final letter or syllable.
1.1 The simplest rule: -o and -a
The rule you learn from day one is this:
- Words ending in -o are generally masculine (el libro, el zapato, el año)
- Words ending in -a are generally feminine (la mesa, la ventana, la semana)
This rule works reliably for adjectives and a large number of nouns. It’s also what allows you to form the feminine of many names for people and professions:
– americano → americana
– abogado → abogada
– simpático → simpática
1.2 Words ending in a consonant
Many nouns and adjectives ending in a consonant are masculine. The feminine is formed by adding -a:
– español → española
– doctor → doctora
– campeón → campeona
Note: when the masculine ends in -ón, the feminine loses the written accent (campeón → campeona).
The same happens with -és → -esa: francés → francesa.
1.3 Words ending in -e
Words ending in -e can be either masculine or feminine, and the form often stays the same for both:
– el/la estudiante
– el/la nicaragüense
– el /la eficiente → the adjective works for both genders
This is especially common with nationalities and nouns referring to people: the ending doesn’t change, but the article does.
However, some nouns ending in -e do have a fixed gender:
Feminine: la carne, la gente, la tele
Masculine: el coche, el pie, el diente
1.4 Gender-invariable words
Some categories of words have the same form in both masculine and feminine:
- Words ending in -a: el/la belga, el/la dentista, el/la optimista
- Words ending in -í: el/la marroquí, el/la israelí
In these cases, it’s the article that signals the gender.
2. The exceptions: words that break the rules
Be careful: the -o masculine / -a feminine rule is not absolute. There are important exceptions you’ll need to learn by heart.
2.1 Feminine words ending in -o
Some words end in -o but are feminine. The most common ones are:
– la mano
– la radio
– la foto (short for fotografía)
– la moto (short for motocicleta)
2.2 Masculine words ending in -a
Some nouns end in -a but are masculine. The most common ones are:
– el problema
– el idioma
– el tema
– el día
– el mapa
3. Special cases: irregular pairs
Some words have completely different forms in the masculine and feminine, without following any general rule. These are high-frequency words, so it’s worth learning them early. We can divide them into three groups.
3.1 Suffix transformations
In these cases, the root is recognisable, but the suffix changes in an irregular way:
| Masculine | Feminine |
|---|---|
| príncipe | princesa |
| rey | reina |
| héroe | heroína |
3.2 Completely different roots
In these cases, the masculine and feminine are entirely distinct words, with no formal link between them — just as in English with “man/woman” or “bull/cow”:
| Masculine | Feminine |
|---|---|
| hombre | mujer |
| toro | vaca |
| el pez macho | el pez hembra |
3.3 The -or / -triz pattern
Some masculine words ending in -or form their feminine with the suffix -triz, rather than simply adding -a. The two most common examples are:
– actor → actriz
– emperador → emperatriz
You’ll recognise this pattern immediately from English: actor → actress, emperor → empress. It’s the same mechanism. This pattern isn’t very widespread in Spanish — only a handful of words follow it — but it’s worth knowing because actor and emperador are extremely common words.
4. Singular and plural: how to form the plural in Spanish
Once you’ve got gender under control, let’s move on to number. The rules here are also fairly regular, with a few cases to watch out for.
4.1 The basic rule: vowel → +s, consonant → +es
The core principle is simple:
- If a word ends in a vowel, the plural is formed by adding -s:
– peruana → peruanas
– hermano → hermanos
– coche → coches
- If a word ends in a consonant, the plural is formed by adding -es:
– español → españoles
– traductor → traductores
– tren → trenes
4.2 Words ending in -z: a special case
Words ending in -z form their plural with -ces. Watch out: the z changes to c before e:
– el pez → los peces
– capaz → capaces
– la vez → las veces
– feliz → felices
This change is purely spelling-based: in Spanish, the [s] sound before e and i is written with c, never with z.
4.3 Invariable plurals
Some words ending in -s don’t change form at all: they look identical in both singular and plural. Gender and number are indicated only by the article:
– el lunes → los lunes
– el análisis → los análisis
– la crisis → las crisis
These words end in -s and their final syllable is unstressed — which is why they don’t change in the plural.
4.4 Words ending in -í and -ú: two accepted forms
Words ending in the stressed vowels -í and -ú can take two plural forms, both of which are correct:
– israelí → israelís or israelíes
– bambú → bambús or bambúes
Both forms are in use, though the -es ending is generally considered more formal.
5. Why does getting gender and number right matter so much?
In Spanish, gender and number don’t just affect the noun itself — they ripple through the entire sentence. Articles, adjectives and participles all agree with the noun they refer to. Get the gender of a noun wrong, and every agreement around it will be wrong too.
Think about wanting to say “the most beautiful day”: if you don’t know that día is masculine, you might say la día más bella instead of the correct el día más bonito. Gender and number are the grammatical foundations of Spanish: building them solidly from the start will save you a great deal of trouble down the line.
6. Want a clear reference sheet to keep handy?
To review the rules quickly and concisely, take a look at the Género y Número grammar sheet in the Sillabi grammar resources. It’s the perfect tool to refer back to while you study or practise.
7. Ready to take your Spanish to the next level?
Understanding gender and number is the first step. But to use these concepts spontaneously, slot them into the right sentences and feel Spanish becoming more and more natural, you need a structured, progressive learning path.
The ¡Ojalá! course is designed exactly for that: a motivating, step-by-step journey with clear explanations, practical activities and real-life contexts to turn grammatical rules into solid language habits.
And if you’re not sure where to begin, take the level test now: in just a few minutes, it will show you the perfect starting point on your learning journey. ¡Hasta pronto!