R&D Tax Credit Belgium — Complete Guide 2026

Belgium offers one of the most attractive fiscal incentives for research and development in Europe. The core mechanism is the partial exemption from payment of withholding tax on the salaries of qualifying researchers. Under the current regime, companies can retain 80 percent of the withholding tax they would normally owe on researcher wages — effectively reducing the cost of employing R&D staff by a substantial margin.

This is not a subsidy or a grant. It is a tax measure administered through the federal payroll tax system. Companies still withhold the full amount from employee salaries, but they remit only 20 percent of that withholding tax to the treasury. The remaining 80 percent stays with the employer. The employee notices no difference — the benefit flows entirely to the company.

The rationale behind this incentive is straightforward: Belgium wants to attract and retain research talent. By making R&D employment significantly cheaper, the government encourages companies to invest in innovation domestically rather than relocating research activities to lower-cost jurisdictions. The measure applies regardless of company size, sector, or region — any Belgian employer with qualifying researchers can benefit.

It is worth noting that this exemption is separate from the innovation income deduction (IID), which reduces taxes on revenue generated by qualifying intellectual property. Companies can use both mechanisms simultaneously, creating a powerful fiscal environment for innovation-driven businesses. For a broader overview of available funding, see the grants directory.

Eligibility depends primarily on two factors: the qualifications of the researchers and the nature of their work. The researcher must hold a qualifying diploma — typically a master's degree or PhD in exact sciences, applied sciences, medical sciences, veterinary sciences, pharmaceutical sciences, engineering, or related fields. A bachelor's degree in certain technical fields can also qualify under specific conditions.

The second condition is that the researcher must be assigned to research or development activities. The Belgian tax authorities follow the Frascati Manual definition of R&D: systematic creative work undertaken to increase the stock of knowledge and to devise new applications of available knowledge. This covers basic research, applied research, and experimental development.

Importantly, the exemption also extends to certain technical support staff who directly assist qualifying researchers, though the rules here are more restrictive. The company must be able to demonstrate that these employees are engaged in genuine R&D activities — routine engineering, quality control, or technical support for existing products typically does not qualify.

Companies must register their qualifying researchers with the Belgian Science Policy Office (BELSPO) and obtain a formal notification confirming that their R&D projects meet the Frascati criteria. This registration is a prerequisite for claiming the exemption and must be renewed or updated when projects change. The AI assistant Lucas can help you assess whether your team and projects are likely to qualify.

The financial impact is significant. For a researcher earning a gross annual salary of €60,000, the employer withholding tax is approximately €16,000 to €20,000 depending on personal tax factors. An 80 percent exemption means the company retains €12,800 to €16,000 per researcher per year. For a team of ten qualifying researchers, this translates to savings of €128,000 to €160,000 annually — a substantial reduction in operational costs.

To claim the exemption, companies must file a specific annex with their regular payroll tax declarations. The process requires identifying each qualifying researcher by name, linking them to registered R&D projects at BELSPO, and calculating the exemption amount per employee. Most payroll providers in Belgium are familiar with this process and can assist with the administrative handling.

The BELSPO notification is the critical step. Companies submit a description of their R&D projects, including the scientific or technological uncertainty being addressed, the methodology, and the expected advancement of knowledge. BELSPO evaluates whether the projects meet the Frascati Manual criteria and issues a notification that covers a defined period — typically matching the project timeline.

There is no cap on the total exemption amount per company. As long as you have qualifying researchers working on registered R&D projects, you can claim the 80 percent exemption for each of them. This makes the measure particularly attractive for R&D-intensive companies where researcher salaries represent a large portion of operating costs.

The R&D wage tax exemption operates entirely through the tax system and is available continuously — there are no application windows, competitive evaluations, or budget ceilings. As long as you meet the criteria, you can claim it. This is fundamentally different from R&D grants through VLAIO, Innoviris, or SPW, which require applications, evaluations, and compete for limited budgets.

Grants provide direct co-financing for specific project costs — they cover a percentage of eligible expenses for a defined project within a defined timeframe. The tax exemption reduces your ongoing payroll costs for all qualifying researchers, regardless of which specific project they are working on. The two mechanisms serve different purposes and address different parts of the innovation funding equation.

Can you combine them? Yes, and this is standard practice for many Belgian companies. You can receive a VLAIO R&D grant for a specific innovation project while simultaneously claiming the wage tax exemption for the researchers working on that project and other projects. There is no double-dipping concern because the grant covers project costs while the tax measure reduces payroll tax obligations — they affect different budget lines.

The most effective strategy for R&D-intensive companies is to build a layered funding approach: use the wage tax exemption as a structural cost reduction for your entire research team, apply for project-specific grants from VLAIO, Innoviris, or federal programs for major initiatives, and leverage the innovation income deduction on revenue from resulting IP. This combination can reduce the effective cost of innovation by 40 to 60 percent depending on the specific programs and project characteristics. For personalized guidance on which combination works best for your situation, consult Lucas.