J. J. Smith

• J. J. Smith (Gaelic footballer), Carlow Gaelic footballer
• J. J. Smith (author), American author, nutritionist and weight management expert
• J. J. Smith or J. J. Sm., Johannes Jacobus Smith, Dutch botanist
• James J. Smith, FBI Supervisory Special agent
• James John Smith (electrical engineer), American applied mathematician
• J. J. Smith (linguist), South African linguistics