IASSC vs GLSS

Honest comparison for Professional Certification in 2026

IASSC

The International Association for Six Sigma Certification (IASSC) provides universally accepted Lean Six Sigma certifications. It's a third-party certifying body — vendor-neutral and globally recognized.

Strengths

Vendor-neutral certification (not tied to any training provider)
Globally recognized Lean Six Sigma credentials
Clear body of knowledge and exam standards
More accessible exam fees than ASQ

Weaknesses

Less brand recognition than ASQ among some employers
Doesn't provide training — certification only
Exam-only model means you need separate study materials

iassc.org

GLSS

Partner

GoLeanSixSigma offers self-paced Lean Six Sigma certification courses — from Yellow Belt through Black Belt. The certifications are recognized industry-wide and used by Fortune 500 companies for process improvement training.

Strengths

Self-paced certification courses
Yellow through Black Belt
Lifetime access
Industry-recognized credentials
Project-based curriculum

Best for

Operations professionals and managers leveling up

Try GLSS →

The verdict

IASSC is better if:

Professionals who want vendor-neutral Lean Six Sigma certification

GLSS is better if:

Operations professionals and managers leveling up