Does my spouse’s certification on the same platform grant permission to work during my L-1B assignment?

No. A professional certificate is not immigration work authorization. Check the spouse’s actual qualifying status and evidence.

Keep skills separate from permission

A qualifying L spouse may work incident to valid status with appropriate evidence, including the relevant spouse-designated I-94. Dependent eligibility may cover an eligible spouse and unmarried children under 21, but children do not receive that spouse authorization. The principal’s transfer and the vendor’s credentials do not themselves grant dependent status.

Households that have moved between assignments usually hold a scattered set of documents across several countries, and the practical advice is to consolidate them before they are needed: each family member's passports including expired ones, birth certificates, school records and any prior immigration documents. Employers sometimes present a first transfer as a development opportunity with a start date already attached, while the questions that actually govern a household move, such as a spouse's employment, schooling, and whether anyone follows later, run on a different clock. If a child turns twenty-one during the assignment, derivative status ends on that birthday whatever the parent's remaining period, and a student route with its own admission and financial requirements takes time to arrange.