Can Polygraphs Be Used Against You in Texas?

If you're being investigated or charged with a crime in Kaufman County, there's a good chance someone has suggested you take a polygraph—or "lie detector test." You might hear:

"If you’ve got nothing to hide, just take the test. It’ll clear everything up."

Sounds simple, right? Wrong.

Here’s what you need to know before you ever agree to take a polygraph in Texas—and especially if your freedom is on the line in Forney, Terrell, or Crandall.

Polygraphs Are NOT Admissible in Texas Courts

This might surprise you, but polygraph results can’t be used as evidence in a Texas criminal trial. The highest criminal court in Texas has made this clear:

"The Court of Criminal Appeals has held that the results of polygraph exams are inadmissible as evidence. See, e.g., Leonard v. State, 385 S.W.3d 570, 577 (Tex. Crim. App. 2012) (op. on reh’g)."

That means prosecutors can’t use a failed polygraph test against you in front of a jury. It’s not considered reliable evidence, and Texas law doesn’t allow it.

But there’s a catch.

If You Don’t Object, You Can Lose That Protection

Even though the law says polygraph results aren’t allowed, you can accidentally allow them into your case if your lawyer doesn’t raise the right objection at the right time. How can this come up? If you are on probation for a case that requires polygraphs, and your probation is being revoked, the State may try to offer evidence that you “failed” a polygraph. This polygraph result is not admissible. However your lawyer must object at the time it is offered. If not, the court may consider these results.

Here’s what the courts say:

"Nonetheless, Texas courts have repeatedly upheld the rule that, to complain on appeal regarding allegedly improperly admitted evidence, a party must make a timely request, objection, or motion with sufficient specificity to apprise the trial court of the complaint." Tex. R. App. P. 33.1(a); see, e.g., Gonzalez v. State, 616 S.W.3d 585, 591 (Tex. Crim. App. 2020); Ethington v. State, 819 S.W.2d 854, 858-59 (Tex. Crim. App. 1991).

It’s happened before:

"Such is the case with complaints regarding the admission of evidence regarding a polygraph exam. Willis v. State, 785 S.W.2d 378, 384 (Tex. Crim. App. 1989) (defendant waived error in mention of polygraph examination by failing to make timely and specific objection)..."

Should You Take a Polygraph in Texas?

No. No. No. No. No. Call us and we will help you. Do not go down to the station for a poly just because some detective asks you to. It’s a setup. Cops are allowed to use polygraphs to interrogate you, and imply that you failed EVEN IF YOU DIDN’T.

The polygraph isn’t being offered to help you. It’s often used to apply pressure and extract a confession. Even though the results aren’t admissible in court, anything you say during the polygraph can be used against you.

And here's what the Court of Criminal Appeals reminds us:

"[T]he results of polygraph examinations are inadmissible over proper objection…" Leonard v. State, 385 S.W.3d 570, 577 (Tex. Crim. App. 2010) (op. on reh’g)

That key phrase—"over proper objection"—is why having the right legal team matters.

Final Word: Don’t Face a Polygraph Alone

If you're under investigation or charged with a crime, call a lawyer before you agree to anything. What feels like a simple test can become a tool to twist your words and trap you in court.

We’re here to help. Contact the criminal defense team at Guest and Gray Law Firm for a free consultation. We’ll walk you through your options and make sure your rights are protected—from the first question to the final verdict.

About Guest and Gray Law Firm

At Guest and Gray Law Firm, we’ve helped hundreds of clients in Kaufman County criminal cases. We have been helping clients with polygraph requests from law enforcement for decades. Whether you're charged with drug possession, assault, DWI, or any other offense, we know how to protect your rights—especially when law enforcement tries to use sketchy  tactics like polygraph exams.