What is a letter of support?
A letter of support is a short document from a partner, stakeholder, or community member that endorses your grant proposal and confirms their commitment to the project. It signals to the funder that people beyond your organization back the work and will contribute to it — through funding, in-kind resources, collaboration, or referrals. It usually runs one page, on the writer's letterhead, signed and dated.
What to include in a letter of support
A strong letter is specific. Funders can tell the difference between a real partnership and a favor.
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Who the writer is and their relationship to your organization or project.
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Specific knowledge of your work — concrete examples, not generic praise.
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What the writer (or their organization) will contribute: funding, in-kind support, referrals, expertise, or collaboration.
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Why the project matters to the community the writer serves.
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A clear statement of endorsement and the writer's contact details, on letterhead and signed.
In Grantable, a support letter lives on your RFP checklist as a tracked attachment — so it doesn't get forgotten at submission.
Letter of support vs. letter of intent
They're easy to confuse but do different jobs. A letter of support is written by a third party — a partner or stakeholder — to endorse your project, and it's submitted with the full proposal. A letter of intent (LOI) is written by you, the applicant, to the funder, early in the process, to briefly describe a planned proposal and gauge interest before you invest in the full application.
In short: a support letter is someone vouching for you; a letter of intent is you raising your hand. Many funders ask for one, the other, or both at different stages — always check the RFP.
Common mistakes
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Generic, interchangeable praise that could describe any organization.
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No specific commitment — funders look for what the partner will actually do.
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Letters that just restate the proposal instead of adding an outside voice.
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Sending the funder a stack of near-identical letters drafted by the applicant.
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Missing letterhead, signature, or date — small things that read as careless.
Frequently asked questions
What is a letter of support?
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A letter of support is a short document from a partner, stakeholder, or community member that endorses your grant proposal and confirms their commitment to the project. It tells the funder that people beyond your organization back the work and will contribute to it — through funding, in-kind resources, collaboration, or referrals. It typically runs one page on the writer's letterhead.
What is the difference between a letter of support and a letter of intent?
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A letter of support comes from a third party (a partner or stakeholder) endorsing your project, usually included with the full proposal. A letter of intent (LOI) is written by the applicant to the funder, early in the process, to briefly describe a planned proposal and gauge interest before submitting the full application.
Who should write a letter of support?
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Choose people with credible, specific knowledge of your work and standing with the funder's priorities: partner organizations, community leaders, beneficiaries, collaborating researchers, or local officials. A specific letter from a genuine partner is worth far more than a famous name who can only offer generic praise.
How long should a letter of support be?
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One page. Funders read many of them, so the strongest letters are concise: who the writer is, their specific knowledge of your work, what they'll contribute, and a clear endorsement — on letterhead, signed and dated.
Can I write the letter of support for someone to sign?
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It's common to provide a partner with a draft or talking points to save them time, but the letter should reflect their genuine voice and commitment, and they should review and edit it before signing. Funders can spot a stack of near-identical applicant-written letters — specificity and authenticity are what give them weight.
Write the whole proposal with less friction.
Grantable drafts proposal sections from your content and turns the RFP into a checklist that tracks every required attachment — including support letters. Free to start.