The Big Brother Rule Book (or simply, the House Rules) is a handbook of rules and regulations created by Big Brother for houseguests during their stay in the house. It plays a major part in the show, and it can affect a houseguest's stay inside the house if he or she violates one or more of the rules, as each violation results in a corresponding punishment.

Big Brother's House Rules may vary throughout each country and season, and are enforced at the sole discretion of production. Some countries may have stricter house rules while others have more lenient ones. Some twists can also alter the season's respective rules and regulations.

International House Rules

The following house rules are the most important rules in the Big Brother House and must be followed by contestants all around the world. If a houseguest were to violate these rules, he or she could face a punishment or ejection.

- Housemates shall have no contact with the outside world.
- All housemates must wear microphone lapels at all times, except when swimming or sleeping.
- Conversations in the Diary Room should always stay confidential. No one should ever share such conversations with other houseguests unless told to do so.
- Whispering inside the house is strictly prohibited. (Whispering is defined as talking too softly for a microphone to detect)
- Housemates should never intimidate, threaten or act violently towards any other housemate.
- Tasks are compulsory, but housemates may be permitted to refrain from participating where health or other reasons are accepted by Big Brother.
- Speaking in another language aside from the official language used by the show is strictly prohibited.
- The housemates should never deliberately break anything inside the house.
- The housemates should never discuss anything related to the outside world. (Selectively enforced)
- Covering or tampering microphones or cameras, writing secret messages, talking under hidden places (such as bedding, tables and beds) are strictly prohibited.
- The Houseguests must leave the house immediately (after brief goodbyes) once evicted and immediately experience an interview with the host on live television.
- Production has the sole discretion over what to broadcast and what not to broadcast.

The following items are forbidden inside the house:
- Drugs and narcotics
- Personal medication (except in consultation with Big Brother)
- Weapons
- Watches
- Money, check books, or credit/debit cards
- Mobile/cell phones
- TVs, Computers, or Gaming Devices
- PalmPilots or electronic organizers
- Agendas or diaries
- Magazines
- Books, aside from official religious texts
- Pens or any similar writing implements (unless provided by Big Brother)
- Paper or writing pads (unless provided by Big Brother)
- Musical instruments (allowed in some countries)
- Any ready-made games, such as playing cards (unless received from production)
- Any item requiring electrical or battery power
- Radios or walkmans
- CDs or CD players
- Clothes entirely white in colour, with prominent commercial logos (unless authorized), or messages to the outside world.

These items will not be returned until the end of the game/if you're evicted from the Big Brother house.

Big Brother US & Canada

In the Big Brother U.S. and Big Brother Canada, the majority of the house rules enforced internationally are also enforced in the house, with key differences regarding how the game is played.

Some of these rules that appear specifically on the North American version include the following; the houseguests are allowed to talk about nominations, as well as influence others to vote; the houseguests aren't given a weekly house budget. Instead, certain houseguests go on slop for a week, determined by either a challenge or the Head of Household.

Big Brother U.S. and Canada Rulebook

The Head of Household must nominate two people for eviction.
The winner of the Power of Veto may elect to remove one nominee from the block, including themselves. If the Power of Veto is golden, the HOH must immediately select a replacement nominee. If it is diamond, the winner of the power must immediately select a replacement nominee.
Houseguests must vote to evict one of the two nominees on live television, unless declared ineligible to vote. Unless otherwise directed, the vote will be cast in the diary room.
Specific rules about the house and how the houseguests are responsible for its maintenance.

Rule Violations & Punishments

A violation is an unlawful action made by a Housemate/Houseguest that is considered as improper conduct in the Big Brother Rule Book. Every violation made has a corresponding punishment.

Most international versions of Big Brother enforce house rules strictly and in the event that a housemate has violated the rule book, he/she would receive a violation strike from Big Brother. The number of strikes would determine which punishment the violator should receive. However, in rare cases where all housemates committed multiple rule violations, Big Brother would give serious punishments to the entire house as disciplinary measures.

Typically, each housemate can only have three strikes of violations which means they can only receive three warnings within their whole stay inside the Big Brother House. Once they had three or more strikes, they automatically face forced eviction.

- 1st Strike: Violators may have a light punishment, usually, punishments that hinder their normal lives in the house such as being tied together for a certain amount of time or giving up important and sentimental objects.
- 2nd Strike: Violators may receive an automatic nomination.
- 3rd Strike: Violators will have to be forcibly evicted out of the house.
Despite having three strikes, there are rules that if violated may result in ejection regardless of the strike count. Some of these grave violations include; violent and threatening behavior, abusive & offensive remarks, and failure to observe the 24-hour Rule.

Violation Announcements

Announcement of Violation Reports may vary from season to season or even different countries. Usually, Big Brother will inform the housemates in the Living Room of those who had a violation for the week. The violators will be shown on television with their committed violations. They will be receiving the punishment afterward.

If the punishment is a "Forced Eviction/Ejection" the violation is usually announced privately inside the Diary Room. Depending on the season, the ejected housemate may leave the house immediately and unannounced, or during a specific day within the week.

Trivia
- Big Brother (U.S.) is the first-ever franchise to revise some of the major house rules in Big Brother due to the changing of the format in Big Brother 2 (US). Revised rules include; the allowing of discussions about Nominations and influencing others to nominate other contestants. Those are considered major violations in the original format as contestants were strictly prohibited of talking about nominations, and doing so may result to either automatic nomination or ejection.
- Big Brother Canada is the only other franchise to follow the American rules of Big Brother.
- Big Brother: Over The Top finalist Kryssie Ridolfi is best known for checking the rulebook after a competition, which has turned into a meme across the fandom.