Abstract: This study assessed the effect of situation analysis on the implementation of a web-based airline reservation system at Topix Agency Limited in Rwanda. The study was guided by systems theory and stakeholder theory. A descriptive survey design using a mixed-methods approach was adopted. The target population comprised 119 employees and stakeholders, from which 108 respondents were selected using Slovin’s formula and stratified random sampling. Data were collected using structured questionnaires, semi-structured interviews, and documentary review. Quantitative data were analyzed using descriptive statistics, Pearson correlation, and multiple regression in SPSS version 27, while interview data were analyzed thematically. Situation analysis was strongly and positively correlated with implementation (r = .670, p < .01) and had a significant positive effect on implementation (β = .658, p < .001) after controlling for other project design practices. The study recommends that the agency institutionalize comprehensive situation analysis, covering stakeholder analysis, problem analysis, and needs assessment, and allow sufficient time for it before and throughout system implementation.