Purpose: This paper seeks to understand what influences research and extension professionals' intentions to use AIS approaches and to explore how this can inform implementation and design of more effective AIS. Methodology: We applied the Reasoned Action Approach through focus groups and structured questionnaires with research and extension professionals from government and non-government organisations in Sierra Leone, where AIS approaches are not widely used although increasingly institutionalised in policy. Findings: Research and extension professionals have surprisingly positive attitudes towards using AIS approaches and associate it with a range of positive outcomes related to food security and inclusive processes. The perceived ability to successfully implement AIS approaches is strongly influenced by funding, organisational culture and dynamics between senior and junior staff. We also found that alongside use of AIS approaches there is a continued adherence to top-down approaches. Practical Implications: This work highlights the enthusiasm and interest among extension and research professionals as a promising start for improving the innovation systems. Practical requirements include training of senior and involvement of junior staff respectively in AIS design, and addressing extension education and organisational culture. Theoretical Implications: This study highlights the importance of socio-psychological theory for understanding attitudes towards AIS approaches. We show how considering both institutional and personal constraints is vital for conceptualising how AIS are evolving. Originality: There has been very little research conducted on research and extension professionals' intentions to use AIS approaches in developing countries that links with personal and systemic preconditions for supporting more effective AIS.