Gambling, though widespread, can negatively impact health and other areas of life. Psychological factors like overconfidence, which includes overestimation and overplacement, can affect gambling behaviours. This study examined overplacement (e.g., how people compare their earning abilities and well-being to others) and its influence on gambling behaviours among Chinese college students and people who gambled in a Macau casino. The researchers found that people who perceived themselves as having higher earning abilities than others had more gambling motivations and gambled more frequently. By contrast, those who considered themselves to have better well-being had fewer gambling motivations and gambling issues. This study highlights the importance of understanding how social comparison affects gambling behaviours.