Ohio Initiated Issue 3 was on the November 5, 1918 ballot in Ohio as an initiated constitutional amendment, where it was approved. Initiated Issue 3 concerned the classification of property for tax purposes.
The provisions of Initiated Issue 3 conflicted with the provisions of another measure on the same ballot, Referred Issue 1. Referred Issue 1 also won a majority of the vote, with 56.36% in favor. In the court case State ex rel. v Fulton (99 O.S. 168), it was decided that since Initiated Issue 3 conflicted with Referred Issue 1, even though both of the measures won an absolute majority, only the measure that won the highest majority would go into effect. That meant that Referred Issue 1 became law, while Initiated Issue 3 did not.
| Initiated Issue 3|
| Yes|| 336,616|| 52.51%|