Irish Twins – Meaning, Origin and Usage

Are you looking for a catchy way to describe two siblings with a very small age gap? The now slightly archaic term Irish twins may be just what you're looking for. Before you choose to use the phrase Irish twins, however, it's wise to understand its history. Keep reading to find out more!


The phrase Irish twins refers to two siblings who were born in close succession, within 12 to 18 months of each other. Although these siblings are not, in fact, twins, the age gap between them is so small that they may functionally act and be raised as twins.

Irish twins has historically been a derogatory term referencing the devout Catholic nature of the Irish nation and the fertility resulting therefrom.

However, it is not all that uncommon for adult siblings who are very close in age to refer to themselves as Irish twins without any negative connotation.

Of course, twins from Ireland can also be called Irish twins — and they could have some fun declaring themselves such when visiting the United States.

Example Usage

Are you curious how the phrase Irish twins might be used in a sentence? Take a look at these examples:

  • (In response to the question "Are you twins?") No, we're just Irish twins!
  • Guess what? I'm pregnant again! I didn't think it would happen so fast but now I'm really looking forward to having Irish twins.
  • Irish twins? Oh no, those aren't twins from Ireland, those are siblings born really closely together.


The country of Ireland has historically been devoutly Catholic, and largely remains so even today. Because of this, any method of birth control has been frowned upon as not being in accordance with the Catholic faith, causing Ireland to become known as a country in which people tend to have extremely large families.

When a mass migration of Irish people to the United States occurred in the nineteenth century, those siblings who were less than a year apart in age came to be referred to as Irish twins because of this stereotype.

It is not necessary for siblings born less than a year apart to be Irish to be called Irish twins; the saying soon expanded to include people not of Irish descent as well. Indeed, Irish twins can be born more than a year apart as well — those born within 18 months of each other may also be referred to as such.

The phrase Irish twins was long considered to be insulting. Its origins should be viewed in the context of the discrimination Irish immigrants to the United States faced.

While some people still consider the phrase Irish twins to be derogatory today, plenty of people use it in a purely descriptive way.

Phrases Similar to Irish twins

You may also come across the phrases "Catholic twins" and "Dutch twins", which have the same meaning. These phrases are, however, far less commonly used.

Phrases Opposite to Irish Twins

There are, interestingly, no equivalent phrases to describe siblings with a very large age gap.

What Is the Correct Saying?

The correct saying is Irish twins, meaning siblings born less than a year (or up to 18 months) apart.

Ways People May Say Irish Twins Incorrectly

The phrase "Irish twins" has become so ingrained in the English language that few stop to think about its origins. Before you use it, you should ideally consider the negative connotations associated with the phrase Irish twins, which some still consider to be offensive.

Do not tell a very fertile and large Catholic family that they have multiple sets of Irish twins, for instance, as you will likely cause offense.

Acceptable Ways to Phrase Irish Twins

You may choose to use the phrase Irish twins to refer to yourself and your sibling if you are, in fact, part of a set of Irish twins. It is best to refrain from calling other sets of siblings Irish twins.

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