Mi vecino y mi abuelo no se llevan bien.

Literally, se llevan bien comes from the verb llevarse bien, which is a reflexive/pronominal verb meaning “to get along (well)”.

• llevar by itself = to carry, to take.
• llevarse bien (con alguien) = to get along well (with someone).

So:

• Mi vecino y mi abuelo no se llevan bien.
  Literally: My neighbor and my grandfather do not carry themselves well (with each other).
  Natural English: My neighbor and my grandfather don’t get along (well).

You can’t translate it word‑for‑word because llevarse bien is an idiomatic expression whose meaning has shifted from the basic verb llevar. English uses a different idiom: to get along.

Se here is a reflexive / pronominal pronoun that is part of the verb llevarse bien. It doesn’t really translate directly into English, but it tells you the verb is being used in this special “get along” sense.

Compare:

• Ellos llevan las maletas. = They carry the suitcases. (llevar, non‑reflexive)
• Ellos se llevan bien. = They get along well. (llevarse bien, reflexive/pronominal)

Without se, no llevan bien would sound incomplete or wrong in this context and would not mean “don’t get along.” The “relationship” meaning only appears with llevarse bien.

The verb must agree with the subject, which is plural:

• Mi vecino y mi abuelo = they (two people) → third person plural.

So:

• Mi vecino se lleva bien con mi abuelo.
  (My neighbor gets along well with my grandfather.) → se lleva (3rd person singular)
• Mi vecino y mi abuelo no se llevan bien.
  (My neighbor and my grandfather don’t get along well.) → se llevan (3rd person plural)

If you used se lleva in the original sentence, it would be grammatically incorrect.

They’re related but used differently:

• llevar (no reflexive pronoun):

  • Llevo el libro. = I carry the book.
  • Él lleva una chaqueta. = He is wearing a jacket.
  • Ella lleva tres años aquí. = She has been here for three years.

• llevarse bien (con alguien):

  • Me llevo bien con mi jefe. = I get along well with my boss.
  • No se llevan bien. = They don’t get along.

So llevarse bien is a fixed expression about personal relationships, not about physically carrying or wearing things.

Not if you want to say “they don’t get along.”

• No se llevan bien = They don’t get along (well).
  This is the standard, clear expression.

If you just say no se llevan, context becomes very important. It could sound:

• Incomplete: like you forgot bien or mal, or
• Like you mean some other use of llevarse (for example, llevarse algo = to take something away, llevarse a alguien = to take someone with you).

So for “not getting along,” you should use no se llevan bien (or less commonly no se llevan nada bien, “they really don’t get along at all”).

Yes, if you specify the person they don’t get along with:

• Mi abuelo no se lleva bien con mi vecino.
  = My grandfather doesn’t get along well with my neighbor.

But in your original sentence, the two people are already the subject:

• Mi vecino y mi abuelo no se llevan bien.
  Here “with each other” is implied, so you don’t need con.

You would not say:

• ✗ Mi vecino y mi abuelo no se llevan bien con. (wrong, it needs an object after con)

Mi is singular and mis is plural:

• mi vecino = my neighbor (one)
• mis vecinos = my neighbors (more than one)

In the sentence, you have two separate singular nouns, each with its own mi:

• mi vecino (my neighbor)
• mi abuelo (my grandfather)

So:

• Mi vecino y mi abuelo no se llevan bien. ✅

If you said mis vecino y abuelo, it would be wrong because:

• mis is plural but vecino and abuelo are singular.
• Also, in Spanish you normally repeat the possessive when referring to two different people: mi X y mi Y.

Yes. Spanish allows you to change the order of coordinated nouns like this:

• Mi vecino y mi abuelo no se llevan bien.
• Mi abuelo y mi vecino no se llevan bien.

Both mean “My neighbor and my grandfather don’t get along (well).”
The difference is only stylistic or about which person you want to mention first; the meaning is the same.

The subject mi vecino y mi abuelo is equivalent to ellos (they). So you can say:

• Ellos no se llevan bien.
  = They don’t get along (well).

Some other useful forms of llevarse bien:

• Yo me llevo bien con él. = I get along well with him.
• Nosotros no nos llevamos bien. = We don’t get along well.
• Ustedes se llevan muy bien. = You (plural) get along very well.

In Spanish, no goes directly before the conjugated verb. When there’s a reflexive pronoun, it stays right before the pronoun:

• Se llevan bien. = They get along well.
• No se llevan bien. = They don’t get along well.

Pattern:

• no + reflexive/indirect/direct object pronoun(s) + conjugated verb

Examples:

• Me gusta. → No me gusta.
• Se ve bien. → No se ve bien.
• Nos llevamos bien. → No nos llevamos bien.

Vecino changes for gender:

• vecino = male neighbor
• vecina = female neighbor

So you’d say:

• Mi vecino y mi abuelo no se llevan bien.
  (My male neighbor and my grandfather…)
• Mi vecina y mi abuelo no se llevan bien.
  (My female neighbor and my grandfather…)

Similarly, abuelo (grandfather) vs abuela (grandmother).

Yes, no se llevan bien is very common and fully natural in Latin America.

Some common alternatives you might hear:

• No se caen bien.
  Literally: they don’t “fall” well (to each other) → they don’t like each other.
• Se llevan mal.
  Literally: they get along badly.
• No se soportan.
  They can’t stand each other.
• No se aguantan.
  They can’t put up with each other.

Your sentence:

• Mi vecino y mi abuelo no se llevan bien.
  is the standard, neutral way to say they don’t get along.