What is illegal in Muay Thai?
I · Intermediate · Fouls and safety · 3 of 4Fouls include biting, head-butting and spitting, pressing on the eyes, locking or bending joints, throwing with the hip or tackling, lifting the opponent, striking a downed opponent and striking the groin or back of the neck. Holding a leg and pushing more than two steps without striking, passive defence and ignoring the referee are fouls too.
How it works
- Dirty tactics: biting, head-butting, spitting, eye pressing, smothering.
- Grappling: joint locks, hip throws, tackles, lifting, leg hooks.
- Down opponent: no striking, falling on or blocking them from rising.
- Illegal targets: the groin and the back of the neck.
- Caught leg: no pushing more than two steps without striking.
- Passivity: covering up completely or falling to avoid strikes.
- Commands: striking after "Yoot" or "Yaek", or before "Chock".
- Ropes: no striking while holding them.
The glossary has the fouls (Muay Thai), the scoring target, the clinch, the referee commands (Muay Thai), the gum shield and the caution.
Tricky cases
Can a fighter sweep an opponent's leg?
Yes, with a Muay Thai technique; a trip without one is a foul.
An accidental low kick hurts the groin. What happens?
The referee may give up to 3 minutes' rest; if the athlete cannot go on, the opponent wins.
Can a fighter strike while kneeling?
No. Only the feet may touch the floor when striking.
Is spitting out the gum shield a foul?
Yes, if done on purpose.
Why the rule exists
Muay Thai allows heavy striking and clinching, so the fouls draw a line at moves that injure without skill. Grappling holds are banned to keep the fight a striking contest.
Where it differs
| Where | What changes | Source |
|---|---|---|
| U14 | No knees or elbows to the head | 31.3 |
| U8 to U12 | No strikes to the head | 31.3 |
| Semi contact | Excessive force is a foul | 31.3.1 |
From the rule book
IFMA, Rules & Regulations for International Competition, version 3.057, rules 29.1.3 and 31.2. Checked 14 October 2026. Official document: the IFMA Rules & Regulations, version 3.057.