Senator O'Brien

• Anna Belle Clement O'Brien
• Charles H. O'Brien
• Duncan T. O'Brien
• Henry L. O'Brien
• James H. O'Brien
• James O'Brien (U.S. Congressman)
• James O'Bryan Jr.
• Jay O'Brien (Virginia politician)
• Jeremiah O'Brien (Maine politician)
• Leo P. O'Brien
• Margaret O'Brien (politician)
• Sean O'Brien (Ohio politician)
• Senator Bryan (disambiguation)
• Shannon O'Brien (Massachusetts politician)
• Ted O'Brien (American politician)