Short answer. No, not automatically. Under Article 1404 and Article 1317 of the Civil Code, a contract signed in your name by someone without authority to represent you is unenforceable against you unless you ratify it, expressly or impliedly, before the other party revokes it.
What the law says
Unauthorized contracts are governed by article 1317 and the principles of agency in Title X of this Book.
Civil Code, Article 1404 — Unauthorized Contracts. Read the full provision →
Unauthorized contracts are unenforceable, not automatically binding
Article 1404 provides that unauthorized contracts are governed by Article 1317 and the principles of agency. Article 1317 in turn states plainly that no one may contract in the name of another without being authorized by that person, or unless the law itself gives them the right to represent that person. Where someone signs in your name without either of those, the contract is not simply void and ignored, nor is it automatically enforced against you; it is unenforceable, a distinct category that leaves its fate undecided until something else happens.
Ratification is what can bind you
The key word in Article 1317 is unless: the contract becomes binding on you only if you ratify it, and ratification can happen expressly, through a clear statement accepting the contract, or impliedly, through conduct that shows you are treating the contract as your own, such as accepting its benefits with knowledge of its terms. Until you ratify it, you are not bound, and you are free to simply do nothing and let the contract remain unenforceable against you indefinitely.
The other party's right to revoke first
Article 1317 also gives the other contracting party a window to act: they may revoke the contract before you ratify it. This means the situation is not indefinitely open-ended for you to ratify whenever convenient; once the other party revokes, your chance to ratify and be bound is gone. In practice, if you learn someone signed your name without authority and you do not want to be bound, the safer course is to make clear, promptly, that you are not ratifying the contract rather than staying silent while your position remains uncertain.
What if the contract was already partly carried out
Whether something you did counts as implied ratification depends heavily on the facts, particularly if you knowingly accepted money, goods, or other benefits under the contract after learning it was signed without your authority. Accepting such benefits with full knowledge of the situation can be read as implied ratification, even without an explicit statement that you approve the contract. That is why it matters to act promptly and clearly once you discover the unauthorized signature, rather than accepting anything connected to the contract while deciding what you want to do about it.
Related provisions
- Civil Code, Article 1404 — Unauthorized Contracts
- Civil Code, Article 1317 — Contracts in the Name of Another (Unauthorized)