International Ice Hockey Federation (IIHF) rules govern Olympic competition. An overview is provided below.

Participants

The men's tournament will feature 12 teams. Each men's team can have a maximum of 25 players. The women's tournament will include eight teams. Each women's roster can include a maximum of 23 players.

Each team, men's and women's, is allowed to dress a maximum of 20 skaters and two goaltenders for a game.

Ice Surface

Olympic competition takes place on a larger ice surface than NHL games, which is often referred to as Olympic-size ice. (One notable exception was the Vancouver Games, which employed NHL-size rinks for logistic reasons). For Olympic competition, the recommended dimensions of the rink are 60 meters (197 feet) long by 30 meters (98.5 feet) wide. In comparison, NHL rinks are 85 feet wide. 

Basics

A team must not have more than six players on the ice while play is in progress. Typically, those players are: one goaltender, two defensemen, and three forwards (two wings and one center). A lesser amount of players can be on the ice as a result of penalties. In addition, a goaltender can be replaced by a skater during a delayed penalty or at any other time of the game, at a team's own risk. 

A regular game consists of three 20-minute periods with 15-minute intermission after the first and second periods. Teams change ends for each period. If any game is tied at the end of regulation time, a five-minute (preliminary-round games), ten-minute (playoff-round games) or twenty-minute (gold-medal game) sudden-death overtime period will be played with teams of four skaters and one goalkeeper each. 

If no goal is scored in overtime, the game will be decided by a shootout. Three players of each team shoot alternately until a decisive goal is scored. If the result is still tied after three shots by each team, the procedure shall continue with a tie-break shoot-out by one player of each team, with the other team starting to take the tie-break shots. The same player can also be used for each shot by a team in the tie-break shoot-out. The game is finished as soon as a duel of two players brings the decisive result. 

Face-offs

A face-off is when a linesman or referee drops the puck into play between two opposing players. Face-offs occur at the beginning of each period and after any stoppage of play. 

Offsides

A player of an attacking team is offsides if he/she precedes the puck into the offensive zone. For a violation of this rule, play is stopped and a neutral zone face-off conducted. 

A player who skates backward into the zone with complete control over the puck is not offside. 

If a defending player carries or passes the puck into the defending zone while an offensive player is in an offside position, no offside is called. 

There is no two-line offside pass rule in international hockey. If an attacking player precedes the puck into the attacking zone, but a defending player is able to play the puck, the linesman raises his arm to signal a delayed offside - except if the puck has been shot on goal. The lineman drops his arm to nullify the offside violation and allows play to continue if the defending team either passes or carries the puck into the neutral zone or if all the attacking players immediately clear the offensive zone by making contact with the blue line. 

Icing

For the purpose of this rule, the center red line divides the ice rink into two halves. The point of last contact with the puck by the team in possession is used to determine whether or not icing has occurred. 

Should a player of a team equal of superior numerical strength shoot, bat or deflect the puck from his own half of the ice beyond the opposing team's goal line, play is stopped and icing is called. A face-off will then take place inside the defensive zone of the offending team. 

No icing is called:

• If the puck enters the goal for a score
• If the puck passes through the goal crease
• If the offending team is short handed at the instant the puck is shot
• If the puck touches any part of an opposing player, including the goalkeeper, before crossing the line
• If the puck is iced directly from a player participating in a face-off
• If, in the opinion of a lineman, any player from the other team, except the goalkeeper, is able to play the puck before it crosses the goal line

Playing the Puck

Players are permitted to stop or bat the puck in the air with an open hand or push it along the ice by hand, unless in the opinion of the referee, the player has deliberately directed the puck to a teammate. 

That same hand pass is legal, however, if the passer and teammate are in their defensive zone. A goal is disallowed if the puck is batted by an attacking player into the goal, even if the batted puck first deflects off an opposing player's body or stick, the goaltender or an official. 

Kicking of the puck is permitted in all zones, but a goal may not be scored by the kick of an attacking player, even if first deflected by any player, goalkeeper or official. No goal may be scored when the stick of an attacking player above the height of the cross bar contacts the puck. 

Goals

A goal is scored:

• When the puck has been put between the goal posts below the cross bar, and entirely across the goal line by the stick of a player of the attacking side
• When the puck is put into the goal in any way by a player of the defending side, and the player of the attacking side who last played the puck is credited with the goal but no assist is awarded
• When the puck deflects directly off the skate of an attacking or defending player into the net
• When the puck is deflected into the goal from the shot of an attacking player by striking any part of the person of a player of the same side. The player who deflected the puck is credited with the goal

A goal is not allowed:

• If the puck has been kicked, thrown or otherwise deliberately directed into the goal by any means other than a stick
• If the net is off its moorings and/or the base of the net is not completely flat on the ice at the time the puck enters the net or crosses the goal line

The following situations are subject to review by the video goal judge:

• Puck crossing the goal line
• Puck in the net prior to the goal frame being dislodged
• Puck in the net prior to, or after the expiration of time at the end of a period
• Puck directed into the net by a hand or kicked into the net
• Puck deflected into the net off a game official
• Puck struck with a high stick, above height of cross bar, by an attacking player prior to entering the net
• To establish the correct time on the official clock provided the game time is visible on the Video Goal Judge's monitors
• Only at the request of the referee or the video goal judge can a play be reviewed.  

Timeouts

Each team is allowed one, 30-second timeout during a game. A skater designated by the coach or the coach himself may ask the referee for the team timeout during a stoppage in play. All players on ice are allowed to go to their respective benches during a timeout. Both teams can take their timeout at the same stoppage of play, but the team taking the second timeout must notify the referee of its intentions before the end of the first timeout. 

A timeout cannot be called:

• During game action
• After a false face-off
• During a penalty-shot shootout
• Before a period has started or after a period has ended
• After player changes have been complete

Replay

New to both the men's and women's tournaments in 2018 is the option of a "coach's challenge" in cases of “offside” play leading to a goal and scoring plays involving potential “interference on a goaltender.”

Penalties

There are several degrees of reprimand available to the referee, depending on the severity of a team or player's infraction: 

• Minor penalty: Any player, other than a goalkeeper, is ruled off the ice for two minutes during which time no substitute is permitted. If the opposing team scores a goal while a team is shorthanded, the penalty is automatically terminated.
• Bench minor: Involves the removal from the ice of one player of the team against which the penalty is imposed for a period of two minutes. Any player, except the goalkeeper of the team, may be designated to serve the penalty by the coach, through the captain, and the player takes his place in the penalty box as if a regular minor penalty had been imposed on him. 
• Double minor: More severe than a minor, but less severe than a major. Basically two minor penalties are assessed to the same player. If a goal is scored before first minor expires, the second minor remains in effect. 
• Major penalty: For the first major penalty in any one game, the offender, except the goalkeeper, is ruled off the ice for five minutes, during which time no substitute is permitted. Unlike a minor penalty, teams with a major advantage may score as many power play goals as possible in the allotted time. For the second major penalty in the same game to the same player or goalkeeper, that player is assessed a game misconduct penalty in addition to the major penalty, and is removed from the contest. 
• Match penalty: Involves the suspension of a player for the balance of the game and the offender is ordered to the dressing room immediately. A substitute player is permitted to replace the penalized player after five minutes playing time has elapsed. For all match penalties, regardless when imposed, a total of twenty-five minutes is charged in the records against the offending player and that player is suspended for the next game.
• Misconduct penalty: A misconduct penalty to any player, except the goalkeepers, involves removal from the game for a period of ten minutes. A substitute player is permitted to replace immediately a player serving a misconduct penalty. A player whose misconduct penalty has expired remains in the penalty bench until the next stoppage of play. When a player receives a minor or major penalty and a misconduct at the same time, the penalized team immediately puts a substitute player on the penalty bench to serve the minor or major. The second misconduct to the same player in the same game automatically becomes a game misconduct
• Game misconduct penalty: Involves the removal of a player or team official for the balance of the game and the offender is be ordered to the dressing room for the remainder of the game. The offender also is suspended for the next game. A substitute is permitted immediately for the player.

Women's and men's international ice hockey operate under the same rules as stipulated by the IIHF - with one fundamental exception: the level of permissible body contact. Since the 1992 World Championship, IIHF rules have prohibited "body checking" in the women's game. 

Physical contact, however, is permitted under the heading "body contact." The distinction between "body checking" and "body contact" is often a subjective one. The IIHF distinguishes between the two types of physical contact as follows:

Body Contact

Intent to play puck first

Minor intent to play the body by players going in same direction

Puck is the major focus

Contact results from playing puck

What is allowed:

Player allowed to hold position

Accidental contact, even for a big collision

No control of the collision by either player

Fending a player off while actively skating

Leaning into an opponent

Minimal board contact

Body Checking

Intent to physically play the body first

Obvious intent to play the body by players going in opposite direction

Focus is on player and not puck

Obvious body check into boards

What is not allowed:

Stepping out of the normal path of the player

Intentional playing only of the body

Checking player controls the situation

Any contact from behind

Propelling hip or shoulder into opponent

Full board contact