Industry-school partnerships offer authentic learning opportunities and can support the development of students' interest in a STEM career. The expectancy-value model of achievement-related choice can help to explain how several factors influence career choice. Interest-enjoyment values and attainment values are most important in students' motivation to participate in out-of-school technology and design activities. Our research question is the following: Is there a development in secondary school students' career interests in science-based technology-related professions while participating in industry-school partnerships? We employed a longitudinal, mixed-methods research design. The sample consists of 213 secondary school students from 9 classes and 72 students from 4 classes in 4 neighbouring schools who served as a control group. All of the students filled out a questionnaire before and after the visit. The questionnaire items were based on scales relating to an expectancy-value model. Four groups of students were interviewed with respect to the industry visit experiences. Analyses indicated that attitudes for applying technology became relevant for predicting career interest in a technology profession in the project group after the end of the project. However, career interest did not increase over time. In the qualitative analysis, four topics emerged that elucidated why career interest did not increase. Overall, the results demonstrate that factory visits combined with embedded tasks are one way to overcome fixed ability self-concepts and allow the students to reconsider a career in the technology and engineering industry towards the end of secondary school.