This study investigated 10th grade boys’ and girls’ self-efficacy and interest in Physics correlated with future intentions and achievement in Physics. 453 10th graders (243 girls and 210 boys) from seven senior high schools located in five different geographic regions in Greece participated in the study. Boys possessed higher self-efficacy and expressed more interest in Physics than girls, while no statistically significant gender differences were found in Physics’ achievement. Both genders expressed negative attitude towards intentions for future choices regarding Physics and disagreed to the social stereotype that engaging in Physics is more suited to men than women. Self-efficacy in Physics emerged as a powerful positive predictor for achievement in Physics and interest in Physics emerged as a powerful positive predictor for future intentions regarding Physics for both genders.