¡No me digas!

Literally, it means Don’t tell me!

But in everyday Spanish, especially as an exclamation, it is very often idiomatic. It usually means something like:

• Really?
• No way!
• You’re kidding!
• Get out of here!

So even though the literal meaning is negative, the real use is often to show surprise, interest, or sometimes sarcasm.

Because negative commands in Spanish use the present subjunctive, not the regular imperative form.

With decir:

• positive informal command: di = tell
• negative informal command: no digas = don’t tell

So:

• Dime. = Tell me.
• No me digas. = Don’t tell me.

This is a very important pattern in Spanish:

• Habla → No hables
• Come → No comas
• Vive → No vivas
• Di → No digas

Me means to me.

In the literal sense, No me digas means Don’t tell me or more exactly Don’t say it to me.

Even when the expression is used idiomatically to mean Really? or No way!, the me stays because that is the fixed expression. The speaker is still the person being told the information.

In Spanish, object pronouns such as me, te, lo, la, nos usually go before a conjugated verb.

So:

• me dices
• no me digas
• te creo
• lo entiendo

With negative commands, the pronoun also goes before the verb:

• No me digas
• No lo hagas
• No te vayas

By contrast, with positive commands, pronouns are attached to the end:

• Dime
• Hazlo
• Vete

Usually, no. In many situations it is a very normal, friendly reaction.

It often expresses:

• surprise
• interest
• disbelief
• playful exaggeration

For example, if someone says they met a famous actor, replying ¡No me digas! can just mean Seriously?

However, tone matters. If said with a dry or sarcastic tone, it can sound like:

• Oh, really?
• You don’t say.

So the phrase itself is not rude, but intonation can change the feeling a lot.

Grammatically, yes, but it usually means something more literal, like Don’t say that or just Don’t speak/tell depending on context.

The common idiomatic exclamation is ¡No me digas!

So if you want the natural reaction meaning Really? / No way!, keep me.

¡No me digas! uses tú, so it is informal singular.

Other versions are:

• ¡No me diga! = formal singular (usted)
• ¡No me digáis! = informal plural in Spain (vosotros)
• ¡No me digan! = formal plural, and also the usual plural form in much of Latin America (ustedes)

In Spain, if you are reacting casually to a friend, ¡No me digas! is the normal choice.

Spanish uses opening and closing exclamation marks:

• ¡ ... !

So ¡No me digas! is written correctly with both.

This is standard Spanish punctuation, not optional in careful writing. The opening mark tells the reader from the start that the sentence is exclamatory.

In standard Peninsular Spanish, digas is pronounced approximately DEE-gas.

A few helpful points:

• di sounds like dee
• g before a is a hard g, like in go
• the stress falls on di: DI-gas

So the whole phrase is roughly:

no meh DEE-gas

The me is usually short and unstressed.

It can be either, depending on tone and context.

Sincere:

• Someone tells you surprising news.
• You reply ¡No me digas! meaning Really?

Sarcastic:

• Someone states something obvious.
• You reply ¡No me digas! meaning You don’t say.

So this is one of those expressions where intonation does a lot of work.

Yes. In Spain, depending on context and level of formality, you might also hear:

• ¿Sí? = Really?
• ¿Ah, sí? = Oh yeah? / Really?
• ¿En serio? = Seriously?
• ¡Anda! = No way! / Really!
• ¡Venga ya! = Come on! / No way!
• ¡No fastidies! = You’re kidding!

But ¡No me digas! is one of the most common and useful neutral reactions to surprising information.

Yes.

It can be a real negative command:

• No me digas nada. = Don’t tell me anything.
• No me digas el final. = Don’t tell me the ending.

It can also be an idiomatic reaction:

• He won the lottery.
• ¡No me digas!

So the meaning depends entirely on context. If there is no additional object and it is said with surprise, it is often the idiomatic reaction.