which one is the correct phrase to say?

I have always been confused by that.

My {younger|little|smaller} sister.

2 Answers 2


The most accurate of the three is "my younger sister". She is, literally, younger than you.

It's very idiomatic, though, to say "my little sister" to mean "younger sister".

"Smaller sister" is not something I've heard and I'd tend to think it would only be used to describe the physical attributes of two sisters, unrelated to their age. For example:

I have two younger sisters, ages 16 and 18 but the older of the two takes after our mom and is smaller in stature, so she's my smaller sister, despite being older.

Similarly, older siblings can be called "big sister" or "big brother" but not "large/r".

  • I find that 'my little sister' is the most natural to say, despite 'younger sister' being more literally accurate.
    – Mitch
    Jun 12, 2015 at 13:43

If you only have one sister and she is younger than you, she is your younger/little/baby sister.

If you have several sisters, it gets more complicated:

The sisters closest to you in age, but younger, are your younger/little sisters.

The youngest sister is then your "baby sister".(US)

  • @GEdgar - Ooops... you're right, of course.
    – Oldbag
    Jun 12, 2015 at 14:44

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