| All American Open | |
| Location: | Niles, Illinois |
| Establishment: | 1941 |
| Course: | Tam O'Shanter Country Club |
| Par: | 72 |
| Tour: | PGA Tour |
| Format: | Stroke play |
| Final Year: | 1957 |
| Month Played: | August |
| Aggregate: | 269 Byron Nelson (1945) |
| To-Par: | −19 as above |
| Final Champion: |  Roberto De Vicenzo |
| Map: | USA#USA Illinois |
| Map Label: | Tam O'Shanter CC |
| Map Relief: | yes |
| Map Size: | 200 |
| Coordinates: | 42.02°N -87.795°W |
The All American Open was a golf tournament on the PGA Tour in the 1940s and 1950s. It was played at the Tam O'Shanter Country Club in Niles, Illinois. It was run by George S. May and was originally known as the Tam O'Shanter National Open. From 1944 to 1946 it offered $10,000 winner's prize. The purses dropped to normal PGA Tour levels when May added the World Championship of Golf to the events played at Tam O'Shanter. May eventually added men's amateur, women's open, and women's amateur "All American" and "World Championship" events, all played at Tam O'Shanter over a two-week period in August. The tournaments were cancelled in 1958 in a dispute between May and the PGA over player entrance fees.
| Year | Winner | Score | To par | Margin of victory | Runner(s)-up | Winner's share ($) | |
|---|---|---|---|---|---|---|---|
| All American Open | |||||||
| 1957 | 273 | −15 | 4 strokes | 3,500 | |||
| 1956 | 278 | −10 | 2 strokes | 3,400 | |||
| 1955 | 277 | −11 | 3 strokes | 3,420 | |||
| 1954 | 277 | −11 | 1 stroke | 3,420 | |||
| 1953 |  Lloyd Mangrum (3) | 275 | −13 | 3 strokes | 3,420 | ||
| 1952 | 271 | −17 | 8 strokes | 3,420 | |||
| 1951 | 274 | −14 | 2 strokes | 2,250 | |||
| 1950 |  Bobby Locke (2) | 282 | −6 | Playoff | 2,500 | ||
| 1949 | Lloyd Mangrum (2) | 276 | −12 | 1 stroke | 3,333 | ||
| 1948 | 277 | −11 | 2 strokes | 5,000 | |||
| 1947 | 276 | −12 | Playoff | 7,000 | |||
| 1946 | 280 | −8 | 1 stroke | 10,500 | |||
| 1945 | Byron Nelson (4) | 269 | −19 | 11 strokes | 10,200 | ||
| 1944 | Byron Nelson (3) | 280 | −8 | 5 strokes | 10,100 | ||
| 1943 | 282 | −6 | Playoff | 2,000 | |||
| Tam O'Shanter National Open | |||||||
| 1942 | Byron Nelson (2) | 280 | −8 | Playoff | 2,500 | ||
| 1941 | 278 | −10 | 1 stroke | 2,000 | |||
Book: Barkow, Al . Al Barkow
. Al Barkow . The History of the PGA TOUR . . November 1989 . 0-385-26145-4 . 86–92 . registration .