Nigeria's Tax Revolution, Why You Have Just 30 Days to Challenge Your Assessment

The Nigerian government has fundamentally restructured how tax collection works, and the implications reach far beyond policy circles. At the heart of this transformation lies a deceptively simple mechanism: a 30-day window that determines whether you'll pay what the government thinks you owe or what you actually owe.

The Clock Starts Ticking the Moment You're Assessed

Here's what makes this reform particularly consequential: the burden of proof has shifted. Tax authorities no longer carry the primary responsibility of getting assessments right the first time. Instead, once they issue a tax bill, you have exactly one month to prove them wrong. Miss that deadline, and the assessment becomes legally binding regardless of its accuracy.

This isn't just an administrative procedure. It's the engine driving Nigeria's ambitious plan to collect at least ₦17.85 trillion ($12.59 billion) in tax and customs revenue throughout 2026. The government is betting that tight deadlines will accelerate revenue collection while forcing taxpayers to engage seriously with their obligations.

Consider the practical reality: a content creator earning ₦5 million monthly receives an assessment claiming they made ₦7 million. If they don't challenge this within 30 days with detailed documentation and precise objections, they're now legally responsible for taxes on the higher amount. Payment becomes mandatory, or penalties follow.

Who This Actually Affects

The reform targets a demographic that has historically operated outside Nigeria's tax framework: freelancers, remote workers, digital creators, and independent contractors. Many in this category will file income taxes for the first time in 2026.

Unlike traditional employees whose taxes vanish from their pay cheques before money reaches their accounts, these workers must navigate self-assessment. They calculate their own income, file their own returns, and now critically must defend those figures if challenged.

The government aims to lift Nigeria's tax-to-GDP ratio from roughly 10% to 18% by 2027. Bringing this informal workforce into the tax net represents a cornerstone of that strategy.

How the Assessment System Actually Works

The process follows a clear sequence, though one that demands attention and organisation.

First, taxpayers voluntarily declare their income and file returns. The tax authority then reviews this submission and responds in one of three ways: accepting it as filed, accepting it while adding supplementary charges, or rejecting it entirely and imposing their own assessment.

For those who don't file at all? The authority determines what's owed based on their best judgement, a calculation that may or may not reflect reality.

This is where documentation becomes critical. The difference between a reasonable tax bill and an excessive one often comes down to paper trails: invoices, bank statements, contracts, and receipts. Taxes in this new system aren't based solely on earnings but on what you can prove you earned.

Challenging an assessment isn't as simple as saying, This seems too high.The law requires objections to be comprehensive and precise.

A valid objection must include the specific errors you're disputing, the exact monetary values in question, the amendments you're requesting, your justification for those changes, your admitted income or transaction values, and the tax amount you acknowledge owing, if any.

This level of detail typically requires professional guidance. Tax attorneys or accountants become necessary, not optional, for anyone facing a disputed assessment.

Once you submit an objection, the authority can request additional documents, summon witnesses, or demand further evidence. If both parties reach agreement, the assessment gets revised and reissued, usually with another 30-day payment window.

Disagreements can escalate to formal appeals. The tax authority has 90 days to respond to legitimate objections. Silence after that period? Your objection succeeds automatically.

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How Nigeria Compares Globally

The 30-day objection window places Nigeria on the stricter end of international standards. South African taxpayers get 80 days. Canadians have 90. Australians enjoy four years to challenge assessments. The United Kingdom also uses a 30-day window, matching Nigeria's approach.

These variations reflect different philosophies about the relationship between tax authorities and citizens. Longer windows suggest governments shoulder more responsibility for accurate initial assessments. Shorter windows transfer that burden to taxpayers while speeding up revenue collection.

When Your Tax Bill Becomes Final

Three scenarios make an assessment legally binding and enforceable:

You fail to file a valid objection or appeal within the 30-day period. You explicitly agree to the assessed income or profit. The amount is confirmed through the objection or appeal process.

Once finalised, payment becomes mandatory. Failure triggers consequences: at least 10% interest on outstanding amounts, plus the authority's power to designate your bank as a collection agent. Your funds can be seized directly.

Tax authorities must maintain detailed assessment lists documenting names, addresses, total profits, tax amounts owed, and any related documentation they deem relevant.

The Real-World Stakes

For Nigeria's expanding class of independent workers, 2026 represents a watershed. The tax system that once largely ignored them is now specifically designed to capture their income.

The 30-day rule might matter more than the actual tax rates. It's not just about how much you pay, but whether you can successfully defend your self-reported income when challenged. Speed and precision become essential skills, alongside the more obvious requirement of actually earning money.

Implementation has sparked significant controversy, but states are beginning to align with the new framework. The Nigeria Revenue Service has commenced operations as the country's central tax authority, signalling that enforcement will follow policy.

Whether this approach succeeds in raising revenue while maintaining fairness depends largely on execution, on how aggressively authorities assess income, how reasonable they prove during objections, and whether taxpayers can realistically meet the documentation standards and tight deadlines the system demands.

The transformation is underway. The question now is whether Nigeria's informal economy can formalise fast enough to meet it.