QuestionI know that laughing out loud invalidates Salah, but what about a quite laugh like that is not as obvious as laughing out loud - does this also invalidate Salah?AnswerAll perfect praise be to Allaah, The Lord of the Worlds. I testify that there isnone worthy of worship except Allaah, and that Muhammad sallallaahu `alayhiwa sallam ( may Allaah exalt his mention ) is His slave and Messenger.Laughing invalidates the prayer if it is loud and boisterous or if two letters or more are articulated when laughing. But it is not invalidated if less than twoletters are articulated and it is not boisterous and it is not invalidated fromsmiling alone.An-Nawawi may Allaah have mercy upon him said:According to our School, smiling does not have a negative effect, nor does laughing if less than two letters are articulated, but if two letters are articulatedthe prayer is invalid. Ibn Al-Munthir reported a consensus of the scholars thatthe prayer becomes invalid by laughing, but this is understood to mean if two letters (or more) are articulated. And he said that most of the scholars said thatsmiling does not have a negative effect. This is the view of Jaabir ibn Abdullaah, Ataa, Mujaahid, An-Nakha i, Al-Hasan, Qataadah, Al-Awzaai, Ash-Shaafii and the As-haab Ar-Ray. However, Ibn Seereen said: "What I know is that smiling is like laughing (i.e. it invalidates the prayer). [End of quote]Ibn Qudaamah may Allaah have mercy upon him said in Al-Mughni:If a person laughs and two letters are articulated, his prayer is valid, as wellas if one laughs boisterously even without two letters. This is the view of Jaabir bin Abdullaah, Ataa, Mujaahid, Al-Hasan, Qataadah, An-Nakhai, Al-Awzaai, Ash-Shaafii and the As-haab Ar-Ray, and we are not aware of anyone having a different opinion. Ibn Al-Munthir said: "The scholars unanimously agreed that laughing invalidates the prayer, and most of the scholars hold that smiling does not invalidate it."Allaah Knows best.