What it is
VA Form 21-10210, Lay/Witness Statement, is the form a third party uses to give VA a written, signed account of what they personally saw, heard, or experienced related to your service or your condition. Under 38 CFR 3.159(a)(2), lay evidence is competent when the person has direct knowledge of facts and describes matters an ordinary person can observe, pain, limping, panic attacks, a specific in-service incident, changes in your behavior after deployment. The witness signs a certification that the statement is true to the best of their knowledge.
When you use it
Use 21-10210 when someone other than you is providing the statement: a battle buddy who saw the IED blast, a spouse describing your nightmares, a coworker watching your back give out, a parent comparing you before and after deployment. You, the veteran, should use VA Form 21-4138 for your own statements, 21-10210 is for witnesses.
What to gather before you fill it out
The witness needs: their full legal name, address, and relationship to you; your name, file number or SSN, and the claim it supports; specific dates, places, and units if known; only firsthand observations, not opinions about whether you should be rated.
How to submit
Upload through VA.gov's Submit Evidence tool attached to your open claim, mail to the Evidence Intake Center at PO Box 4444, Janesville, WI 53547-4444, or fax to 844-531-7818. Keep a copy.
Common pitfalls
Witness writes secondhand information they were told by someone else. VA gives that little weight. Witness offers a medical diagnosis or nexus opinion they are not qualified to give. Statement is vague ("he was never the same") with no dates, events, or observed behaviors. Form is unsigned or undated. Veteran fills it out for the witness and forges a signature, that is a federal crime.
Related forms
VA Form 21-4138 (Statement in Support of Claim) for your own statements. VA Form 21-0781 for PTSD stressor details.
Sources
https://www.va.gov/find-forms/about-form-21-10210/ • 38 CFR 3.159(a)(2), https://www.law.cornell.edu/cfr/text/38/3.159