Is a moving allowance my employer pays me when I relocate for work a taxable benefit?

It depends on how the allowance is structured and what it's actually covering. A moving or relocation allowance can be tax-free to the extent it reasonably reimburses your actual moving costs for an eligible relocation — reasonable, documented expenses connected to a genuine work-related move are the kind of thing this more favourable treatment is meant to cover.

Where it becomes a taxable benefit is when the allowance goes beyond that: a flat lump sum that exceeds what your actual, reasonable moving costs were, or an allowance paid in a situation that isn't really tied to an eligible relocation in the first place, is more likely to be treated as taxable income rather than a tax-free reimbursement. The core question is whether the payment is genuinely reimbursing real costs tied to a qualifying move, or whether it's functioning more like extra compensation dressed up as a moving allowance.

Because the line between a reasonable reimbursement and an excessive lump sum depends on your specific costs and the nature of the relocation, it's worth keeping receipts and documentation for actual moving expenses, and having a clear understanding with your employer about how the allowance is characterized, rather than assuming any amount labelled a "moving allowance" is automatically tax-free.