The Short Answer

Generally, no. In Florida, your sibling cannot legally sign your name to estate or insurance documents unless they have valid legal authority to act for you (such as a properly granted power of attorney) or they are signing in a different legal capacity (for example, as the court-appointed personal representative of an estate).

If a sibling signs your name without authority, that can be treated as an unauthorized signature and may also expose them to serious civil and criminal consequences depending on the document and intent.

What Florida Law Says

Florida law draws a hard line between (1) someone signing for you with legal authority and (2) someone signing as you without authority. When a person signs another person’s name without permission or legal authority, the signature is generally not valid as the other person’s signature, and it can trigger fraud/forgery issues—especially with documents like insurance policies, deeds, wills, and other instruments.

The Statute

The primary law governing this issue is Fla. Stat. § 673.4031.

This statute establishes that an unauthorized signature is generally ineffective (though it may be ratified in some situations), and it also makes clear that civil or criminal liability for making an unauthorized signature is not eliminated just because a document might be treated as effective in limited circumstances.

In addition, Florida’s criminal forgery statute specifically includes documents like a policy of insurance and other important writings. See Fla. Stat. § 831.01.

One important exception in the probate context: a person may be able to sign certain documents for the estate if they are the properly appointed personal representative. Florida law gives personal representatives broad authority to administer estate assets and execute necessary instruments. See Fla. Stat. § 733.612.

If you want more background on probate-related fraud concerns, you may find this helpful: Florida probate options when fraudulent documents or identity theft threaten an inheritance.

Why You Should Speak with an Attorney

Even when the rule sounds straightforward (“they can’t sign for you”), the real-world outcome often depends on what was signed, who relied on it, and what authority (if any) your sibling claims. Legal outcomes often depend on:

• Strict Deadlines: Some claims tied to a death, probate administration, or beneficiary disputes can be time-sensitive, and waiting can limit your leverage or remedies.
• Burden of Proof: You may need evidence showing the signature was unauthorized (and, in some cases, whether a bank/insurer relied on it in good faith or whether anyone later “ratified” it).
• Exceptions and Capacity Issues: A sibling may have authority if they are a court-appointed personal representative, a trustee, or an agent under a valid power of attorney—or they may claim you “approved it,” which can become a factual dispute.

Because unauthorized signing can overlap with probate administration, insurance proceeds, and potential fraud/forgery allegations, it is easy to make a misstep that harms your rights or escalates conflict. A Florida probate attorney can quickly identify what authority existed, what documents are impacted, and what remedies are realistically available.

If your situation involves a sibling acting under claimed authority, you may also want to read: challenging a sibling’s actions under a Florida power of attorney.

Get Connected with a Florida Attorney

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Disclaimer: This article provides general information under Florida law and does not create an attorney-client relationship. Laws change frequently. For legal advice specific to your situation, please consult with a licensed attorney.