In Spain, people normally have two surnames by law, and there are fairly clear rules on how those “double surnames” work.

Basic rule: two surnames

  • Spanish nationals are generally required to have two surnames, not one.
  • Traditionally, the pattern was: first surname from the father + first surname from the mother (for example, Juan García López: García from dad, López from mom).
  • Today this is still the usual pattern, but the order is no longer automatically “father then mother.”

Order of surnames (since 2018)

  • Since a law change that came into force on 30 June 2018, parents can decide which surname goes first for their children (within the first few days after birth).
  • That means a child can legally be, for example, “López García” instead of “García López,” as long as both parents agree.
  • Once the order is chosen for the first child of a couple, the same order must be used for all their later children , to keep sibling surnames consistent.
  • If the parents cannot agree on the order, the Civil Registry official decides it.

Where each surname comes from

In standard cases (two Spanish parents, both with two surnames):

  • Child takes one surname from each parent, normally the first surname of each.
  • Example:
    • Father: Luis García Sánchez
    • Mother: María López Díaz
    • Child: Enrique García López (or Enrique López García, if parents choose that order).

Special family situations:

  • Single parent: the child usually takes both surnames from that parent (e.g., Ana Pérez Pérez or Ana Pérez Gómez, depending on the parent’s own surnames).
  • Two mothers / two fathers: the child still takes one surname from each parent (or both from the biological/adoptive parent, depending on the legal situation and adoptions).
  • Adoption: when adopted by a married couple, the child normally takes one surname from each adoptive parent, regardless of their sex.

Double‑barrelled surnames inside the two-surname system

Spain distinguishes between:

  • The two required surnames (legal rule: you must have two surnames).
  • Whether each of those surnames is simple or double‑barrelled (joined with a hyphen or with particles like “de,” “del,” etc.).

Legally there are four basic patterns:

Structure Example
Simple first surname + simple second surname Lucía Vega Torres
Simple first surname + double-barrelled second surname Lucía Vega Torres-Luna
Double-barrelled first surname + simple second surname Lucía Vega-Luna Torres
Double-barrelled first surname + double-barrelled second surname Lucía Vega-Luna Torres-Serrano
Key points:
  • The law cares that you have two surnames in total , not whether each is simple or double‑barrelled.
  • Many “double” surnames for aristocratic or historically important families were created to preserve status or recognisability (e.g., combining two family names and treating them as a single compound surname).

Using and writing the surnames in practice

  • On official documents (ID, passport, tax records, etc.), both surnames must appear , in the exact order registered.
  • In everyday life, people often use just the first surname when introducing themselves or in informal settings (e.g., “Señor García,” even if the full name is García López).
  • For families, it is common to refer to them using both surnames of one member, for example “familia Corchado Resmella” to mean the whole family unit.

What happens at marriage?

  • Marriage does not change surnames in Spain: women do not legally take the husband’s surname, and men do not take the wife’s.
  • Each spouse keeps their own two surnames before and after marriage; children’s surnames are set according to the rules above.

Changing the surnames later

You can change surnames, but it is limited:

  • It is possible (but not automatic) to reverse the order of your surnames, correct spelling, or register a surname you have habitually used.
  • There are exceptional cases for deeper changes, such as those linked to gender transitions or serious identity and safety issues.

International forms and “surname confusion”

When Spaniards interact with systems designed for only one surname:

  • Many forms in English-speaking countries expect: given name + middle name + single surname, but Spaniards usually have no middle name and two surnames.
  • This often leads to software treating the first surname as a “middle name” and the second as the “true” surname, causing mismatches between tickets, visas, and passports.
  • Rule of thumb:
    • If a form has “First surname” and “Second surname,” fill them literally.
    • If there is only one surname field, use the first surname, unless the authority explicitly wants both.

Mini example to tie it together

Imagine:

  • Father: Carlos Ruiz Martínez
  • Mother: Elena Gómez Torres

If they agree to follow tradition (father first, mother second):

  • Child: Laura Ruiz Gómez

If they agree on the reverse order:

  • Child: Laura Gómez Ruiz

In both cases, Laura has two surnames, one from each parent, ordered according to the parents’ choice and fixed for any siblings that come later.

Information gathered from public forums or data available on the internet and portrayed here.