Are there occupations that OINP will not accept?

Yes. OINP streams restrict eligibility to specific NOC codes or TEER (Training, Education, Experience and Responsibilities) levels. Occupations at lower TEER levels (TEER 4 and 5, which require minimal formal training) were generally not eligible for OINP's former skilled worker or graduate streams; the Ontario Workforce Priority stream now has a dedicated TEER 4-5 pathway for in-demand occupations alongside its TEER 0-3 pathway.

For Express Entry-linked streams, federal Express Entry eligibility itself restricts which occupations qualify — TEER 0, 1, 2, and 3 are covered; TEER 4 and 5 are generally not, with some limited exceptions. Since the Ontario Workforce Priority stream's Express Entry-linked pathway (which replaced the former HCP and French-Speaking Skilled Worker streams) draws from the Express Entry pool, you must have a qualifying occupation in the first place to appear in that pool.

For the former Employer Job Offer streams, OINP published lists of eligible occupations (or TEER levels) for each sub-stream; the Ontario Workforce Priority stream sets its own occupation requirements per pathway. Certain occupations may also be restricted if they are regulated in Ontario and the applicant does not have or is not on a path to provincial licensing (e.g., certain health professions).

If your occupation appears on a restricted or ineligible list, it does not necessarily mean you have no immigration pathway — you may qualify under a different stream or through the federal Express Entry system using a different occupational history. A detailed assessment of your full work history is worthwhile before concluding you have no options.