Wal-Mart Stores Inc. broke with major European retailers on Tuesday by announcing its own plan for improving safety at Bangladesh garment factories. The plan is billed as a commitment, but is different from the legally-binding pact meant to prevent disasters like the building collapse that killed more than 1,100 garment workers last month.

Under its plan, Wal-Mart said it would hire an outside auditor to inspect 279 Bangladesh factories and publish results on its website by June 1. When fire and building safety issues are...