Does an Ontario limited partnership need a written limited partnership agreement?

Ontario's Limited Partnerships Act requires a declaration to be filed to register the limited partnership, but it doesn't necessarily require the underlying agreement between the general and limited partners to be in writing as a strict legal precondition. That said, treating a limited partnership agreement as optional would be a mistake in practice, given how much rides on the document.

A limited partner's liability protection depends on staying out of the business's control, and the limited partnership agreement is typically what defines the limited partners' rights (such as information rights and consent rights on major decisions) precisely enough to let them stay informed without crossing into control. It also typically covers how profits and losses are allocated, what happens if a limited partner wants to exit or transfer their interest, and the general partner's obligations and compensation. Without a clear written agreement, the parties are left relying on default statutory rules that may not reflect what they actually intended, and limited partners may struggle to show what oversight they were entitled to exercise without risking their protection. In practice, a written agreement is essential, not optional.