The Mutual Combat Defense in Illinois

 Posted on December 24, 2025 in Criminal Law

Two adults in Illinois can decide to fight each other. In some cases, adults decide to fight for fun, such as with wrestling or martial arts competitions. In other cases, it is less clear whether both adults agreed to fight.

Bar fights are a common example where people may disagree about whether everyone involved wanted to participate. So when does a fight cross the line from mutual combat to assault? When can you claim self-defense if you have been charged with assault? If you have been charged with battery, assault, or another violent crime, you’ll want our experienced Rolling Meadows criminal defense attorney.

Is Mutual Combat Legal In Illinois?

Mutual combat is not a formal legal defense in Illinois, but it can serve as a practical defense against criminal charges. When both parties voluntarily agree to fight, prosecutors may have difficulty proving that one person committed an assault or battery against the other.

The mutual combat defense recognizes that sometimes two or more people make a conscious decision to physically fight. If everyone involved willingly participated, then prosecutors are far less likely to consider one person a victim and another person an aggressor. They are less likely to press charges as a result.

Illinois law under 720 ILCS 5/12-3 defines battery as knowingly causing bodily harm to another individual without legal justification. However, if you can show that the other person agreed to the fight, you may be able to avoid a conviction. The key is demonstrating that both parties consented to the fight.

Can You Get Criminally Charged In a Street Fight?

You can be charged with assault or battery after a street fight, even if both people participated willingly. Police officers responding to fights typically arrest one or both parties, and prosecutors decide whether to file charges.

In Illinois, assault is a Class C misdemeanor with penalties of up to 30 days in jail and a $1,500 fine. If the fight involved a deadly weapon or resulted in someone getting seriously hurt, charges can be increased to a Class 4 felony with penalties of up to three years in prison and $25,000 in fines.

Beyond criminal penalties, a conviction can change your life forever. It can be very difficult to find a job or a good place to live. Getting out ahead of these charges by working with a good criminal defense attorney is the best way to protect your future. 

When Does Mutual Combat Defense Apply?

While the mutual combat defense might be used if you actually agreed to fight each other verbally or in writing, you do not necessarily have to go that far. In some cases, the agreement can be implied by body language or in a few words during an argument.

Imagine a typical bar fight. A few heated words are exchanged, and then two men stand facing each other with their fists raised for a few moments. Both men step forward and start fighting at the same time. In this example, the court might believe that each party made the conscious decision to voluntarily engage in mutual combat.

Contrast this with a situation in which one of the men stood with their fists raised while other man stepped backward with his hands flat and his palms facing outward in a "stop" gesture. The man with raised fists then steps forward and strikes the other. Only then does the second person fight back. This situation is more likely to be deemed a criminal assault and battery on the first person's part and lawful self-defense on the other's.

What Are the Limits of a Mutual Combat Defense?

Even if you were provoked, using deadly force or a deadly weapon means you cannot use mutual combat as a defense. Mutual defense applies to hand-to-hand combat, not serious violence that resulted in or could have resulted in death.

Mutual combat only applies when both people are equally willing to fight. If one person is significantly larger or stronger and uses that advantage to severely injure the other, this defense may not apply. The force used must be reasonable. Additionally, mutual combat cannot be used as a defense in certain prohibited locations like schools or courthouses.

How Is Mutual Combat Different From Self-Defense?

Self-defense is a true legal defense that requires you to show that you believed:

• Force was necessary

• The force used was reasonable

• It was used against someone breaking the law, and danger was imminent

Mutual combat acknowledges that both parties voluntarily chose to fight. You do not need to prove imminent danger or attempted retreat. Instead, you show both parties willingly participated. If deadly force was used during a non-consensual assault, you may have a self-defense claim rather than a mutual combat defense.

Can I Claim Self-Defense if I Am Charged With Assault or Battery?

You can sometimes argue you acted in self-defense if you are charged with assault or battery in Illinois. Self-defense means you used force to protect yourself or someone else from harm. Under 720 ILCS 5/7-1, you are allowed to use force when you reasonably believe it is necessary to defend yourself against someone who is about to hurt you.

However, you must show that a reasonable person in your situation would also have believed they were in danger. The amount of force you used must match the threat you faced. For example, if someone pushes you, you cannot respond by stabbing them. 

The danger must also be immediate, meaning you were about to be hurt right then, not at some point in the future. Self-defense is different from mutual combat because in self-defense, you do not want to fight and only use force because you have to protect yourself.

Contact a Rolling Meadows, IL Assault Defense Attorney Today

Our Cook County violent crimes defense lawyer at Scott F. Anderson, Attorney at Law will analyze your case and use any defense available to avoid conviction or get reduced charges. We understand that fights happen, and not every fight should result in a criminal record. Contact Scott F. Anderson, Attorney at Law at 847-253-3400 for a free consultation.