Students' causal attributions play an important role in recent studies due to their effects on academic self-concept and performances. Most common causal attributions are students' ability, effort, task difficulty, and chance. The present study aims at identifying students' preferred causal attributions of failure and success while experimenting. Therefore, the experimentation-related causal attribution questionnaire was developed and used on a sample of 90 upper secondary school students. Its factorial validity, internal consistencies, as well as the autonomy of its eight subscales--success- and failure-related causal attributions based on students' ability, effort, task difficulty, and chance in experimentation--were confirmed. Further analyses revealed a gender difference in experimentation-related causal attributions. Girls show less favourable attribution styles than boys in case of both, success and failure. With regard to experimentation-related successes, boys show a higher attribution to ability than girls. Girls are more likely to use luck and a low degree of task difficulty as an explanation for their academic successes in experimental settings than boys. Female students also draw on attributions such as lack of ability and task difficulty to account for their failures. Practical consequences for science education are derived from the findings.