Collecting multiple perspectives data (e.g. from related individuals) in a qualitative longitudinal design can provide rich understanding of the dynamics at play in complex relational systems, and the different perceptions of people involved. However, such approaches are inherently challenging due to the complexity and volume of data involved. So far, little attention has been paid to the methodological challenges of data analysis in multiple perspectives longitudinal research. This paper contributes to the development of a systematized analysis process for multiple perspectives qualitative longitudinal interviews (MPQLI). We present a framework for handling the complexity and multi-dimensionality of MPQLI, describing discrete steps in such analyses, and related aims and insights. We exemplify the suggested strategies with our own research on the transition to parenthood. The proposed framework can increase both traceability and credibility of analysis of MPQLI, and help to realize the potential of multiple perspectives longitudinal interviews.