Pete O'Brien (1890s second baseman) should not be confused with Pete O'Brien (1900s second baseman).
| Pete O'Brien | |
| Position: | Second baseman |
| Bats: | Right |
| Throws: | Right |
| Birth Date: | 16 June 1867 |
| Birth Place: | Chicago |
| Death Place: | York, Illinois |
| Debutleague: | MLB |
| Debutdate: | August 2 |
| Debutyear: | 1887 |
| Debutteam: | Washington Nationals |
| Finalleague: | MLB |
| Finaldate: | June 16 |
| Finalyear: | 1890 |
| Finalteam: | Chicago Colts |
| Statleague: | MLB |
| Stat1label: | Batting average |
| Stat1value: | .273 |
| Stat2label: | Home runs |
| Stat2value: | 3 |
| Stat3label: | Runs batted in |
| Stat3value: | 16 |
| Teams: |
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Peter James O'Brien (June 16, 1867 – June 30, 1937) was a Major League Baseball player. He played in one game for the Washington Nationals in 1887 and 27 games for the Chicago Colts in 1890.