Are there special rules for serving a lawsuit on the Ontario government or a Crown agency?

Yes — suing the government generally involves additional procedural requirements beyond serving a private individual or corporation. Legal documents typically need to be served on a specific government office rather than an individual civil servant, and there are usually separate advance notice requirements that apply before certain claims against the government can even be started, in addition to the ordinary rules for serving a defendant. Crown agencies and government bodies can also have their own specific service requirements that differ from claims against the province directly, so confirming exactly who or what office should be served, and what advance notice steps apply, is an important early step rather than something to work out after the fact.

Because these requirements are specific to government litigation and can affect whether a claim is even properly started, getting this wrong risks real procedural problems later, including a claim being challenged on the basis that proper notice or service was never given. Given how specialized this area is, and how much it can vary depending on which government body or agency is actually involved, confirming the specific procedural requirements that apply to your particular claim before serving anything is genuinely worth doing early.