What Is Offside in Football? A Simple Guide to Law 11

Football offside diagram showing an attacking player, the second-last defender, the ball and the offside line used to determine an offside position.

Offside is one of the most important rules in football, but it is also one of the rules that can be difficult to understand. When a goal is disallowed because of offside, the decision can sometimes seem confusing, especially when the attacker is only slightly ahead of the defender.

So, what is offside in football?

Offside is an offence that can occur when an attacking player is in an offside position when a teammate plays or touches the ball and the player then becomes actively involved in play. Being in an offside position by itself is not an offence. The player must also become involved in play in one of the ways defined by Law 11.

The official Laws of the Game are maintained by the International Football Association Board (IFAB), and Law 11 deals specifically with offside.

Understanding offside becomes much easier when you separate the rule into two parts:

1. Offside position
2. Offside offence

This guide explains both, including the second-last defender rule, the offside line, active involvement, exceptions, VAR decisions and common examples.

For anyone learning how to read football statistics, understanding offside is also useful because it provides context for goals, assists, attacking runs, disallowed goals and match events.”

What Is the Offside Rule in Football?

The offside rule prevents attacking players from gaining an unfair positional advantage by staying too close to the opponent's goal while waiting for a teammate to pass the ball.

According to Law 11, a player is in an offside position when:

• Any part of the player's head, body or feet is in the opponents' half, excluding the halfway line.
• Any part of the player's head, body or feet is nearer to the opponents' goal line than both the ball and the second-last opponent.

The hands and arms are not considered when determining an offside position. The upper boundary of the arm is considered to be in line with the bottom of the armpit.

However, being in an offside position is not automatically an offside offence.

A player becomes punishable for offside only when they become involved in active play under the conditions described by Law 11.

What Does "Offside Position" Mean?

Imagine an attacker standing close to the opponent's goal.

If the attacker has moved beyond the second-last opponent and is also ahead of the ball when a teammate plays the ball, that attacker may be in an offside position.

The important point is that the position is judged at the moment the teammate plays or touches the ball, rather than when the attacker eventually receives it.

For example:

• A striker is standing behind the second-last defender.
• The striker is also closer to the goal than the ball.
• A teammate then plays a forward pass.
• The striker runs onto the pass.

The striker was in an offside position when the teammate played the ball.

If the striker subsequently becomes involved in active play, an offside offence can be called.

Who Is the Second-Last Defender?

One of the most misunderstood parts of the offside rule is the second-last opponent.

A player does not necessarily have to be behind the last outfield defender.

The goalkeeper is normally one of the opponents considered when determining the offside line. Therefore, if the goalkeeper has moved out of position, another defender may become the last opponent while a different player becomes the second-last opponent.

The offside position is judged against the second-last opponent, the ball and the halfway line.

A player is not offside if they are level with the second-last opponent or level with the last two opponents.

Example

Suppose a goalkeeper is standing near the edge of the penalty area while a defender is closer to the goal.

The defender may effectively become the last opponent and another player may be the second-last opponent.

The attacking player's position must therefore be compared with the correct offside line rather than simply the last defender.

When Is a Player Actually Offside?

This is where the distinction between offside position and offside offence becomes important.

A player in an offside position is penalised when they become involved in active play by:

• Interfering with play.
• Interfering with an opponent.
• Gaining an advantage from being in an offside position.

1. Interfering With Play

An attacker can be penalised for offside when they play or touch the ball after being in an offside position when their teammate played or touched it.

For example:

A midfielder plays a through ball to a striker. The striker was in an offside position when the pass was made and then controls the ball.

The referee can stop play for an offside offence.

2. Interfering With an Opponent

A player can also commit an offside offence without touching the ball.

For example, an offside attacker could obstruct an opponent's ability to play the ball by clearly blocking their line of vision.

Law 11 also covers situations where an offside player challenges an opponent for the ball, clearly attempts to play a nearby ball in a way that impacts an opponent, or makes an obvious action that affects an opponent's ability to play the ball.

3. Gaining an Advantage

An attacker can be penalised if they were in an offside position and then gain an advantage from a rebound, deflection or save.

For example:

A striker is offside when a teammate shoots. The goalkeeper saves the shot and the ball falls to the striker, who scores.

The goal can be disallowed because the striker gained an advantage after being in an offside position.

When Is a Player Not Offside?

There are several important situations where a player can receive the ball without being penalised for offside.

There is no offside offence when a player receives the ball directly from:

• A goal kick
• A throw-in
• A corner kick

These are specific exceptions in Law 11.

For example, an attacker can stand beyond the second-last defender and receive a ball directly from a throw-in without committing an offside offence.

Does the Ball Matter for Offside?

Yes.

An attacker must generally be nearer to the opponents' goal line than both the ball and the second-last opponent to be in an offside position.

This means a player can sometimes appear to be beyond the defensive line but still be onside if they are level with or behind the ball.

For example, if a forward receives a backward pass while positioned ahead of the defenders but behind the ball, the forward may not be in an offside position.

This is why the position of the ball is just as important as the position of the defenders.

What Parts of the Body Count for Offside?

When determining offside position, officials consider the player's:

• Head
• Body
• Feet

The hands and arms are excluded for all players, including goalkeepers. The upper boundary of the arm is considered to be the bottom of the armpit.

This can make extremely close decisions difficult because an attacker may be onside with their feet but offside because another legal scoring part of the body is beyond the offside line.

What Happens If an Attacker Is Level With the Defender?

If the attacker is level with the second-last opponent, the player is not in an offside position.

The same applies if the player is level with the last two opponents.

The offside law therefore does not require an attacker to have a clear amount of space between themselves and the defender.

Even a very small difference can become relevant if a part of the attacker's head, body or feet is nearer to the goal line than the relevant defender and ball.

What Is the Offside Line?

The offside line is an imaginary line used to determine an attacking player's position relative to the second-last opponent and the ball.

In modern football, television graphics and VAR systems can display this line to help viewers understand extremely close decisions.

The referee and assistant referee do not simply judge whether the attacker's entire body is beyond a defender.

Instead, the relevant parts of the body are considered according to Law 11.

How Does VAR Check Offside?

Video Assistant Referee (VAR) technology can review potential offside decisions in competitions where VAR is being used.

VAR officials examine the moment when the teammate plays or touches the ball and determine the attacker's position at that instant.

The review can involve multiple camera angles and technology designed to establish the relevant positions.

VAR does not change the basic offside law. It assists match officials in applying the existing law.

What Is the Offside Rule for Goals?

If an attacker is in an offside position and then becomes involved in active play in a way that constitutes an offence, a goal resulting from that action can be disallowed.

For example:

Situation:
A striker is behind the second-last defender when a teammate plays a through ball.

Next:
The striker runs onto the ball and scores.

Decision:
If the striker was in an offside position at the relevant moment and became involved in play, the goal can be disallowed.

However, not every goal involving a player who was initially in an offside position is automatically disallowed.

The exact sequence matters.

IFAB's examples include situations where a player initially in an offside position does not interfere with play, and a teammate later plays the ball when that player has moved into an onside position. In such a case, the goal can be allowed.

Can a Defender Deliberately Playing the Ball Reset Offside?

Yes, but this area of the law requires careful distinction.

If a defending player deliberately plays the ball and an attacker in an offside position subsequently receives it, the attacker is generally not considered to have gained an advantage merely because they were previously in an offside position.

Law 11 distinguishes between a defender deliberately playing the ball and situations involving a rebound, deflection or deliberate save.

For example, if a defender has control of a ball and deliberately kicks it, an attacker who was previously in an offside position may be able to play the ball without being penalised for offside.

However, a deliberate save is treated differently.

What Is a Deliberate Save in Offside?

A deliberate save occurs when a player stops, or attempts to stop, a ball that is going into or very close to the goal.

This matters because an attacker in an offside position can still be penalised for gaining an advantage after a deliberate save.

For example:

1. An attacker is offside when their teammate shoots.
2. A defender or goalkeeper makes a save.
3. The ball falls to the offside attacker.
4. The attacker scores.

The goal can be disallowed because the attacker gained an advantage from the save.

Is Offside Called From a Goal Kick?

No.

A player can receive the ball directly from a goal kick without committing an offside offence, even if the player would otherwise have been in an offside position.

This is an important exception to remember.

Is Offside Called From a Corner Kick?

No.

There is no offside offence when a player receives the ball directly from a corner kick.

This means an attacker can position themselves behind the defensive line before a corner and receive the corner directly without being penalised for offside.

Is Offside Called From a Throw-In?

No.

A player receiving the ball directly from a throw-in cannot be penalised for being offside.

This is another specific exception contained in Law 11.

What Is the Punishment for Offside?

When an offside offence occurs, the defending team is awarded an indirect free kick from the location where the offence occurred.

This applies even if the player who committed the offence is in their own half when the offence occurs.

The referee normally signals an offside offence by raising the flag, with the assistant referee helping identify the offence.

Common Offside Examples

Example 1: Through Ball

A striker stands behind the second-last defender. A teammate plays a through ball and the striker runs onto it.

If the striker was in an offside position when the teammate played the ball and becomes involved in play, an offside offence can be given.

Example 2: Attacker Behind the Ball

A forward is beyond the defenders but remains behind the ball when their teammate passes it backward.

The forward is not in an offside position because the player is not nearer to the opponents' goal line than both the ball and second-last opponent.

Example 3: Corner Kick

An attacker is standing behind the defensive line when a corner is taken and receives the ball directly from the corner.

There is no offside offence.

Example 4: Goalkeeper Save

A striker is offside when a teammate shoots. The goalkeeper saves and the ball falls to the striker.

If the striker plays the ball, the striker can be penalised for gaining an advantage from the offside position.

Example 5: Defender Deliberately Plays the Ball

A defender deliberately plays the ball and it reaches an attacker who had previously been in an offside position.

Depending on the circumstances, there may be no offside offence because the ball came from an opponent's deliberate play.

Offside vs Onside

Why Is the Offside Rule Important?

The offside rule helps maintain a balance between attacking and defending.

Without an offside rule, attackers could remain close to the opponent's goal and wait for long passes throughout a match.

Offside encourages attackers to time their runs and defenders to coordinate their defensive line.

It is therefore an important part of tactical football.

Teams can deliberately use an offside trap, where defenders move forward at the right moment to leave an attacker in an offside position when the pass is played.

Offside Trap Explained

An offside trap is a defensive tactic designed to catch an attacking player beyond the permitted offside line when a teammate plays the ball.

For example, several defenders may move forward immediately before an attacking midfielder attempts a through pass.

If the attacker is then in an offside position at the moment the pass is played and becomes involved in play, the assistant referee can signal for offside.

The tactic requires timing and coordination because a poorly executed defensive movement can instead leave an attacker in a legal position with space to attack.

Understanding attacking passes also becomes easier when you know what is a key pass in football and how these passes create scoring opportunities.

Why Do Offside Decisions Cause So Much Debate?

Offside decisions can be controversial because the rule can depend on extremely small positional differences.

A player may appear level with a defender from one camera angle but have a body part slightly closer to the goal from another angle.

Modern VAR technology has made these decisions more visible because viewers can see detailed replays and offside lines.

However, the fundamental question remains the same:

Was the attacker in an offside position when the teammate played or touched the ball, and did the attacker subsequently become involved in active play?

That is the central question behind most offside decisions.

How to Remember the Offside Rule

A simple way to remember the rule is:

Position + Timing + Involvement

Position

Was the attacker in the opponents' half and nearer to the goal line than both the ball and second-last opponent?

Timing

Where was the attacker when the teammate played or touched the ball?

Involvement

Did the attacker interfere with play, interfere with an opponent or gain an advantage?

If all the relevant conditions are satisfied, an offside offence may have occurred.

Final Thoughts

Understanding offside becomes much easier once you stop thinking of it simply as "being behind the last defender."

The modern rule is more precise.

An attacker must first be in an offside position, and that position is judged when a teammate plays or touches the ball. The player must then become involved in active play for an offence to occur.

The rule also contains important exceptions for goal kicks, throw-ins and corner kicks, while deliberate play by an opponent and deliberate saves can produce different outcomes.

For anyone learning how to read football statistics, understanding offside is also useful because it provides context for goals, assists, attacking runs, disallowed goals and match events.

Article Source Credit:

The official reference for the current Law 11 is the IFAB Laws of the Game.