Yes, you should include your W2s and/or 1099s if you are mailing the SD 100. If it is being e-filed, you do not have to mail anything in.
Per the OH Instruction Booklet, Page 50: "Place legible state copies of your W-2(s), W-2G(s) and/or 1099-R(s) after the last page of the SD 100. Do not Staple or attach."
Click here for the full Ohio 2017 Instruction Booklet.
