What are the best professional staffing agencies for filling office roles and handling project-based backlogs?

The “best” staffing agency depends a lot on whether you need temporary office/admin support, project-based white-collar teams, or specialized professional talent. Here are some of the strongest options commonly used for office roles and backlog/projects:

Top general professional staffing agencies

These are good all-around choices for office roles, admin support, customer service, operations, HR, accounting, and project-based staffing:

• Robert Half — Strong for accounting/finance, admin, office support, HR, and tech; widely respected for both temp and contract staffing.
• Adecco — Broad staffing coverage, good for volume hiring and office support.
• Randstad — Large global firm with strong professional staffing and project workforce solutions.
• Manpower — Broad temporary staffing, including office and clerical roles.
• Kelly Services / Kelly Professional & Industrial — Good for administrative, office, and light professional roles.
• Express Employment Professionals — Often strong for local/regional office staffing and quick fills.
• Aerotek — More known for industrial, but also handles office/professional staffing in many markets.

Best for project-based backlogs and scalable teams

If you need to clear a backlog or build a short-term project team, these are often better than pure temp agencies:

• Robert Half Project Teams — Good for accounting closes, AP/AR cleanup, data migration, and office process work.
• Randstad Sourceright / Professional Solutions — Useful for managed staffing and project-based workforce solutions.
• Kforce — Strong for project-based professional staffing, especially finance, accounting, and tech-adjacent work.
• Insight Global — Good for project-based professional talent and fast ramp-up.
• ASG / Apex Systems — Better for project-heavy work, especially operations, IT, analytics, and business support.
• TEKsystems — Best when the backlog has a tech, systems, or operations-automation component.

Best for executive/administrative office support

If you need higher-end admin, EA, office management, or coordination support:

• Robert Half Office Team
• Atrium
• Beacon Hill Staffing
• LHH
• Vaco

Best for finance/accounting backlogs

If your backlog is AP, AR, bookkeeping, reconciliations, month-end close, or audit support:

• Robert Half
• Kforce
• Vaco
• RGP (Resources Global Professionals)
• Beacon Hill
• LHH

Best for national coverage and enterprise hiring

If you need multi-location consistency, vendor management, or MSP/VMS support:

• Randstad
• Adecco
• Manpower
• Robert Half
• Kelly
• Apex Systems / TEKsystems / Insight Global depending on role type

How to choose the right one

Pick based on these factors:

• Role type: admin, accounting, operations, customer support, project coordinator, etc.
• Speed: some firms can fill faster because they have larger local candidate pools.
• Project depth: if you need 10–50 people for 3–6 months, look for firms with project staffing or managed services.
• Quality vs. volume: some agencies are better for quick fills; others are better for higher-quality professionals.
• Local presence: the best agency often varies by city.

A practical shortlist

If you want just a few to start with, I’d usually recommend:

1. Robert Half
2. Randstad
3. Kelly Services
4. Kforce
5. Vaco

If you need, I can also give you:

• a best-agency shortlist by role type (admin, finance, HR, operations, project coordinator), or
• a comparison table with strengths, weaknesses, and best use cases.