Global professional services company with 700,000+ employees providing comprehensive cloud migration strategy, implementation, and management services.
Top Rated15+ YearsEnterprise
Cloud Migration & ModernizationApp Modernization & Legacy MigrationThe Top 10
The absolute best in legacy modernization
Global consulting and IT services leader providing comprehensive cloud migration and transformation services across all major platforms.
Top Rated15+ YearsEnterprise
Cloud Migration & ModernizationLegacy Modernization
Global IT services company with extensive cloud migration practice, serving businesses with secure workload transitions across all major platforms.
Top Rated15+ YearsEnterprise
Cloud Migration & ModernizationApp Modernization & Legacy Migration
Big Four professional services firm providing comprehensive cloud migration and digital transformation services across all major cloud platforms.
Top RatedEnterprise
Cloud Migration & ModernizationLegacy Modernization
Global consulting leader with comprehensive cloud migration services across AWS, Azure, Google Cloud, and Oracle, specializing in enterprise transformations.
Top Rated15+ YearsEnterprise
Cloud Migration & ModernizationApp Modernization & Legacy Migration
Leading global IT services company with robust cloud migration practice spanning strategy, execution, and managed services.
Top Rated15+ YearsEnterprise
Cloud Migration & ModernizationLegacy Modernization
Mainframe modernization specialist focused on replatforming legacy applications to cloud-ready solutions with typical savings of 60-80%.
Top Rated15+ YearsMid-Size
App Modernization & Legacy MigrationLegacy Modernization
Global technology company driving continuous modernization through CloudSMART strategy and AI Force platform for automated code refactoring.
Top RatedGoogle PartnerAWS Partner+3 more
Legacy ModernizationAI/ML Development
Global IT services company providing legacy application modernization services for complex, business-critical systems with expertise in mainframe technologies and custom tool development.
Top Rated15+ YearsEnterprise
Legacy ModernizationCustom Software Development
Global IT services provider with comprehensive cloud migration solutions tailored for diverse industries and complex enterprise requirements.
Top Rated15+ YearsEnterprise
Cloud Migration & ModernizationLegacy ModernizationTop 10 Legacy Modernization Agencies — FAQ
Common questions about the best legacy modernization agencies.
Who is the #1 legacy modernization agency in the USA in 2026?
As of 2026, the top-ranked legacy modernization agency in the USA on AgencyCluster is Accenture, with an AgencyCluster Score of 100/100. Rankings are based on verified evidence across credibility, proof of work, reputation, category specialization, delivery maturity, and freshness. Rankings are updated periodically as new evidence becomes available.
How were the top 10 legacy modernization agencies in the USA selected?
This list features 10 agencies selected from AgencyCluster's curated directory. Each agency was evaluated using the AgencyCluster Score (0–100), with particular weight on demonstrated expertise in legacy modernization. Only agencies with verified credentials are eligible, and rankings cannot be purchased. The agencies on this list average 50+ years of experience. For full methodology details, see our How We Rank page.
What should I look for when choosing a legacy modernization agency from this list?
Ask for case studies with measurable outcomes relevant to your specific project. Check team composition — do they have specialists or generalists? Ask about their communication cadence and project management approach. Request client references from companies of similar size and complexity to yours.
How much do the top legacy modernization agencies typically charge?
Project costs vary significantly based on complexity, team size, and engagement model. Request proposals from 3–5 agencies to benchmark pricing. Be cautious of quotes that are dramatically lower than others — they usually indicate corners being cut.
Trusted Rankings
Every agency on this list has been reviewed by our editorial team. Rankings are based on our transparent methodology which evaluates credibility, outcomes, and reputation.
No paid rankingsVerified credentialsUpdated regularly
Found an error? Submit a correction