A Letter of Support is a letter from a partner organization, major donor, grant maker, congressional representative, or other key stakeholder that details a compelling and persuasive reason why a grant funder should support your grant application or proposal. It describes how the partner will support the project (as applicable), conveys enthusiasm for the project, and lends credibility to your work. It is often submitted with a proposal or application for grant funds.
Letters of support are frequently from other organizations that have agreed to be a partner for the project your organization is proposing. Sometimes this type of support letter takes the form of a formal partnership agreement, which some grant makers now require.
A second type of support letter is from community leaders who support your proposed program, other entities that may collaborate with you, or groups of people who will receive the services you propose.
If you plan to partner with another nonprofit, the arrangement must be spelled out in writing, either with a letter of support or what is called an interagency agreement or memorandum of agreement. These agreements must explain how the project will be carried out, and how funds from the grant maker will be used.