A lay witness is a witness who testifies based on ordinary personal knowledge rather than specialized expert opinion.
In plain language, a lay witness tells the court what they saw, heard, did, received, observed, or personally experienced. The witness usually cannot give technical expert conclusions unless a rule allows the specific opinion.
Why it matters
Lay-witness testimony matters because most trials rely heavily on ordinary witnesses. A lay witness can establish events, identity, timing, conversations, conditions, and observations.
The term also matters because courts draw boundaries between permitted lay observations and expert testimony that requires specialized qualification.
Where it appears
Lay witnesses appear in depositions, affidavits, direct examination, cross-examination, witness lists, trial subpoenas, and credibility disputes.
Practical example
A store customer testifies that they saw liquid on the floor before another customer slipped. That witness is testifying as a lay witness from personal observation.
How it differs from nearby terms
A lay witness differs from an expert witness. An expert witness gives opinions based on specialized knowledge, training, education, or experience.
It also differs from testimony, which is the broader category of sworn statements by witnesses.
Related terms
Quick knowledge check
Question: What is the usual basis for lay-witness testimony?
Answer: Personal knowledge and ordinary observation.