Definition of as long as

Short definition: The phrase as long as is used to say that something is acceptable, possible, or will happen only if a certain condition is met, and it often sounds natural, flexible, and reassuring in everyday English.

Looking for a clear and natural explanation of the phrase as long as? The phrase as long as is very common in both spoken and written English. It is often used to talk about conditions, requirements, or limits that must be met for something else to happen. You will hear it in rules, agreements, explanations, and everyday conversation. Depending on context, it can also relate to time or duration. Below, each meaning is explained in a calm and natural way, with enough detail to feel clear, human, and practical.

Forms: as long as
Related: if conj., provided that phrase, while conj.
Syllable: as long as

1. (Conjunction phrase) Used to introduce a condition that must be met for something else to happen.

   As long as is used to state a requirement or condition that needs to be true before another action or result can occur, emphasizing that the second situation depends directly on the first and will not happen unless that condition is satisfied.

   You can stay here as long as you follow the rules and respect everyone in the house.
   She said she would help as long as everyone agreed to work together honestly.
   The plan will succeed as long as the team communicates clearly and consistently.

   Synonyms: if, provided that, on condition that, so long as, assuming that, given that, only if, under the condition that, contingent on, depending on, subject to, conditional on
   Antonyms: regardless of, even if not, without condition, no matter what, unconditionally, irrespective of, anyway, despite that, without requirements, freely, without limits, independent of

2. (Conjunction phrase) Used to describe how long something continues in time.

   As long as can also refer to duration, meaning that something happens or remains true during the entire period that another situation continues, linking two actions across the same stretch of time.

   I will wait here as long as the store remains open this evening.
   The lights stay on as long as someone is inside the building.
   He promised to support her as long as she needed help.

   Synonyms: while, during the time that, for the duration that, so long as, throughout the time that, at the same time, during, all the time that, until the end that, for as long as, continuously while, over the period that
   Antonyms: after, before, once finished, no longer when, at the end of, following that, outside the time, beyond the period, once stopped, after it ends, when finished, after completion