A tiered supplier is a supplier classified by its position in a multi-level supply chain, usually based on how directly it supplies an original equipment manufacturer, prime contractor, or final assembler.
In manufacturing, a Tier 1 supplier typically supplies directly to the OEM or prime. A Tier 2 supplier supplies a Tier 1 supplier, and a Tier 3 supplier supplies a Tier 2 supplier. The same company can occupy different tiers depending on the product, program, or customer relationship.
Tiered supplier structures are commonly used in procurement, supplier quality, materials planning, traceability, and supply chain risk management. They help describe where parts, materials, outside processing, or technical data move across the extended supply base.
A supplier tier is not the same as a supplier rating, approval status, or quality score. It describes supply chain position, not necessarily performance, risk level, or certification status.