Since the approval of the 1997 Official Plan, a number of new secondary plans have been created and incorporated into the Official Plan document:
| Official Plan Amendment | Adoption | Approval |
| OPA #3 - Bristol Survey Secondary Plan | Adopted by Milton Council - December 15, 1998 | Approved by Halton Region - September 22, 1999 |
| OPA # 4 - Central Business District Secondary Plan | Adopted by Milton Council - December 14, 1998 | Approved by Halton Region -November 23, 1999 |
| OPA #7 - 401 Industrial / Business Park Secondary Plan | Adopted by Milton Council - June 12, 2000 | Approved by Halton Region - February 20, 2001 |
| OPA #15 - Sherwood Survey Secondary Plan | Adopted by Milton Council - July 26, 2004 | Approved by Halton Region - December 24, 2004 |
| OPA # 29 - Derry Green Corporate Business Park Secondary Plan | Adopted by Milton Council - June 14, 2010 | Pending approval by Halton Region |
| OPA # 30 - Boyne Survey Secondary Plan | Adopted by Milton Council - June 14, 2010 | Pending approval by Halton Region |
| OPA #31 - Conformity Amendment (Growth Plan for the Greater Golden Horseshoe and the Sustainable Halton Plan) | Adopted by Milton Council - June 14, 2010 | Pending approval by Halton Region |
At a Special Council Meeting on June 14, 2010, Town Council passed By-law No. 069-2010 . This by-law adopted OPA 31, being an amendment to bring the Town's Official Plan into conformity with the Growth Plan for the Greater Golden Horseshoe and the Sustainable Halton Plan. Prior to adoption, Section 5.3.3.10 was further amended by Council by Verbal Resolution #630-10.
The text of the amendment can be downloaded in parts as provided below. Further, for the convenience of the reader, a "tracked change" version of the amendment has been consolidated into Town's Official Plan.
OPA 31 - Text (including By-law 069-2010)
OPA 31 - Consolidated "Tracked Change" Version