Prayer: Laughing During Prayer: Does It Invalidate the Salah?

Practical Laws of Islam as per the teachings of Imam Khamenei

Prayer: Laughing During Prayer: Does It Invalidate the Salah?

English:

Question #503:

Does it invalidate the prayers if a person laughs in the middle of his prayers upon recalling a joke or due to a humorous event?

Answer #503:

The prayer will be invalid if the laughter is intentional and loud (guffaw).

-Imam Khamenei, Practical Laws of Islam, Importance and Conditions of Prayer