A formal, legally‑informed agreement between two or more organisations that sets out what information will be shared, for what purpose, on what lawful basis, and under what safeguards. An ISA defines roles and responsibilities, governance, review arrangements, and accountability for the sharing of personal and sensitive information.

Difference from an Information Sharing Protocol:

An Information Sharing Agreement is specific and binding between named parties, whereas an Information Sharing Protocol provides high‑level principles and guidance for information sharing across a partnership or system and may sit above or inform multiple individual agreements.