| Ernesto R. Knollin | |
| Birth Date: | 23 May 1888 |
| Death Date: | June 1981 (aged 93) |
| Coach Sport1: | Football |
| Coach Years2: | 1924–1928 |
| Coach Team2: | San Jose State |
| Coach Sport3: | Baseball |
| Coach Years4: | 1925–1928 |
| Coach Team4: | San Jose State |
| Coach Sport5: | Soccer |
| Coach Years6: | 1918 |
| Coach Team6: | Stanford |
| Overall Record: | 14–22–2 (football) 27–14–1 (baseball) 0–2 (soccer) |
| Championships: | Football 1 CCC (1928) |
Ernesto R. Knollin (May 23, 1888 – June 1981) was an American football, baseball, and soccer coach.
Knollin was the head soccer coach at Stanford University in 1918, tallying a mark of 0–2.[1]
Knollin served as the head football coach at San Jose State University, from 1924 to 1928, compiling a record of 14–22–2.
Knollin was also the head baseball coach at San Jose State, from 1925 to 1928, amassing a record of 27–14–1.