Can changes in rollup summary field cause the trigger to fire in salesforce?

Hi Mohit,

Yes, Changes in rollup summary field can cause trigger to fire.

If the record contains a roll-up summary field or is part of a cross-object workflow, performs calculations and updates the roll-up summary field in the parent record. Parent record goes through save procedure. If the parent record is updated, and a grandparent record contains a roll-up summary field or is part of a cross-object workflow, performs calculations and updates the roll-up summary field in the grandparent record. Grandparent record goes through save procedure.

So,when the child record is saved and the field feeds into the roll-up summary the parent trigger is executed.

Hope this helps you.

Thanks