Truman Lake is the biggest. Is more bigger then the Ozarks Lake.
What Is The Largest Lake In Missouri?
Lake of the Ozarks is known to be the largest lake in Missouri. The lake covers the area of 17,626-acre and popular for a variety of recreational activities.
Lake of the Ozarks, with Table Rock Lake, a close second. 
Depends on what you mean by largest; I asume surface area
1. Truman 55,600 acres
2. Lake of the Ozarks 54,000 a
3. Table Rock 43,100 a
However if you want the most water then that's the other way around because of the depth. Table Rock is 90ft deeper than the others.
1. Table Rock 150.8 billion cubic feet
2. Lake of the Ozarks 86.4b c/ft.
3. Truman 51.5b c/ft.