Can I be personally sued for unpaid payroll deductions if my Ontario company does not remit?

Yes. The Income Tax Act and the Employment Insurance Act both create personal liability for directors of a corporation that fails to remit source deductions — income tax, CPP, and EI — when due. CRA can assess a director personally for the unremitted amounts, plus penalties and interest, even after the company has been wound up or gone bankrupt.

The liability is joint and several, meaning CRA can pursue any or all directors for the full amount. There are defences available. A director who resigns more than two years before the assessment is generally not liable. A director may also escape liability by showing they exercised the degree of care, diligence, and skill that a reasonably prudent person would exercise in comparable circumstances — sometimes called the due-diligence defence.

This defence is fact-specific: taking active steps to ensure payroll was filed (monitoring accounts, following up with the bookkeeper, seeking legal advice early) tends to support the defence. Simply being a non-involved or "silent" director is not automatically a defence.