Autre chose and quelque chose d’autre both mean “something else” or “anything else.” They overlap heavily in meaning, but they are built differently, and one fits more naturally than the other depending on the sentence.

Meaning and structure

Autre chose is a fixed phrase that behaves as a single unit, roughly “other thing.” Nothing can be inserted between autre and chose.

• Vous voulez autre chose ? – “Do you want something else?”
• Parlons d’autre chose. – “Let us talk about something else.”
• Je pensais à autre chose. – “I was thinking about something else.”

Quelque chose d’autre is built from quelque chose (“something”) plus d’autre (“else”). It means the same thing and is just as correct.

• Je veux quelque chose d’autre. – “I want something else.”
• Y a-t-il quelque chose d’autre que vous pouvez faire ? – “Is there something else you can do?”
• Elle cherchait quelque chose d’autre. – “She was looking for something else.”

Adding a description

Both phrases can be followed by de and an adjective. This is where a common misconception comes up: some guides claim autre chose cannot take an adjective this way, and that only quelque chose d’autre can. That is not correct. The Larousse dictionary itself gives autre chose de as standard French.

• Donnez-moi autre chose de meilleur. – “Give me something better.”
• Y a-t-il autre chose de nouveau ? – “Is there anything else new?”
• Je veux quelque chose d’autre de moins cher. – “I want something else that is cheaper.”

In practice, autre chose de is the more natural, more common way to add a description. Quelque chose d’autre de also occurs, but stacking two de elements makes it sound a little heavier, so it turns up more in careful or written French than in casual speech.

Fixed expressions with autre chose

Autre chose appears in a few set phrases with meanings of their own.

• C’est tout autre chose. – “That is a completely different matter.”
• Si tu me l’expliques, c’est autre chose. – “If you explain it to me, that is different.”
• Autre chose, je dois te parler d’un problème. – “Another thing, I need to talk to you about a problem.”

Register

Autre chose is the shorter, more casual choice, and is the one heard most often in everyday speech. Quelque chose d’autre is not formal as such, but it tends to show up more in longer or more deliberate sentences.

• Tu veux autre chose à manger ? – “Do you want something else to eat?”
• Désirez-vous quelque chose d’autre à manger ? – “Would you like something else to eat?”

Common mistakes

• An adjective cannot go directly between autre and chose. Je veux autre plus belle chose is wrong. Say je veux autre chose de plus beau or je veux quelque chose d’autre de plus beau instead.
• The two structures should not be combined. Autre chose d’autre is redundant and incorrect. Use one phrase or the other, not both.

Similar expressions

• C’est une autre affaire – “That is a different matter,” used for a stronger contrast than autre chose.
• N’importe quoi d’autre – “Anything else at all,” with a sense of indifference to which one.
• Rien d’autre – “Nothing else,” the opposite of both autre chose and quelque chose d’autre.

Summary

• Autre chose and quelque chose d’autre both mean “something else” or “anything else,” and are largely interchangeable.
• Autre chose is a fixed unit and the more common, everyday choice.
• Quelque chose d’autre is built from quelque chose plus d’autre, and tends to appear in longer or more deliberate sentences.
• Both phrases can take de plus an adjective; autre chose de is the more natural of the two.