IntroductionA moderated mediation model was constructed in this study to clarify the relationship between family background and self-efficacy of adolescent table tennis players, focusing on the mediating effect of technical learning engagement in the relationship as well as the moderating role of factors such as gender and training years.Methods189 adolescent table tennis players (age: 13.69±1.28 years) were investigated as subjects using a questionnaire method.Results(1) Family background, technical learning engagement, and self-efficacy were significantly and positively correlated (p<0.01), with girls’ technical learning engagement (Mfemale=5.81, Mmale=5.19,p<0.01) and self-efficacy (Mfemale=3.34, Mmale=2.66,p<0.01) significantly higher than boys’; (2) Technical learning engagement partially mediated the effect of family background on self-efficacy (ab=0.10, boot SE=0.02,95% CI=[0.07, 0.14]); (3) The first half of technical learning engagement’s mediating role was moderated by gender (B=0.05,p<0.01), with a more significant influence of family background on boys’ (B=0.24,p<0.001, 95% CI=[0.22, 0.26]) technical learning engagement than girls’ (B=0.19,p<0.001, 95% CI=[0.17, 0.21]); (4) The second half of technical learning engagement’s mediating role was moderated by training years (B=–0.21,p<0.001), with a more significant influence of technical learning engagement on the self-efficacy of adolescents with fewer training years (B=0.54,p<0.001, 95% CI=[0.39, 0.68]). The positive effect of technical learning engagement on self-efficacy gradually diminished with increasing training years, and the moderating effect of training years disappeared when the training years reached 8.94 years.Conclusion(1) More attention should be paid to adolescent table tennis players with poor family backgrounds, who are more likely to have low self-efficacy. (2) Parents should never neglect their initiative in providing guidance and support to adolescent players involved in long-term professional table tennis training, especially for boys. (3) Coaches should pay close attention to the level of technical learning engagement of players with long training years, who are more likely to have lower self-efficacy as a result of their own emotional experiences, stagnant performance, etc.