The inter-generational participatory co-design project (IPCP) was a theory-guided intergenerational project aiming at eliminating ageism by way of intergenerational contact in an innovative educational experience in higher education. Mixed-method evaluation was adopted with quantitative evaluation conducted before and after the project, supported by post-project individual interviews. Students reported significantly improved attitudes toward older adults (p = 0.042; d = 0.60). Follow-up focus group interviews with students qualitatively examined the factors associated with the improved attitudes toward older adults. The study provides insights for the model of an intergenerational learning experience in tertiary education.