Today, there's a new term for represent level of generation, it is called Generation X, Y, Z, and "baby boomer", each of them had a difference in knowledge, experience, and of course the year of birth. This research aims to analyze Self-Efficacy differences within generation X and generation Y, while also analyzing the impact on private company employee job performance. Using quota sampling, 80 questionnaires are distributed and 62 respondents are responding the all the questions in the survey processes. The results of research statistical tests show that there is no significant difference between self-efficacy between generations X and Y on their performance. Practical implications are also discussed in this paper.