This study explored how ethical leadership can influence the sustainability of LNGOs in Rwanda specifically looking at three dimensions including leader integrity, employee engagement, and compliance with management rules and regulations. To address the research objectives, the researcher used a descriptive research design with a mixed method of quantitative and qualitative data. The target population was 119 leaders in 52 LNGOs members of PRO-FEMMES /Twese Hamwe. Hence, purposively the 2 respondents were selected from each of the organizations under PRO-FEMMES / Twese Hamwe to make 104 respondents among leadership positions. The study used a survey questionnaire to collect data. The questionnaire was administered to 100 respondents selected while 4 respondents were given interviews based on the criteria that they are board members of the big umbrella Pro-femmes which implies they are capable to give more detailed data in a form of qualitative data. The results show an overall mean of 4.233 showing that respondents strongly agreed that leaders' integrity influences sustainability of LNGOs in Rwanda. supported by correction analysis results showing a positive and significant relationship between leaders' integrity and institutional sustainability (r=0.933 and sig=0.00), leaders' integrity and financial sustainability (r=0.959 and sig=0.00), leaders' integrity and programmatic sustainability (r=0.973 and sig=0.00). Hence, this shows that there is a positive and significant relationship between leaders' integrity and sustainability of LNGOs in Rwanda. The overall mean of 4.276 implies that respondents strongly agreed that employee engagement influences sustainability of LNGOs in Rwanda. These results are supported by correlation analysis results which show a positive and significant relationship between employee engagement and institutional sustainability (r=0.967 and sig=0.00), employee engagement and financial sustainability (r=0.993 and sig=0.00), employee engagement and programmatic sustainability (r=0.993 and sig=0.00). Hence, this shows that there is a positive and significant relationship between employee engagement and sustainability of LNGOs in Rwanda. The overall mean of 4.238 shows that respondents strongly agreed that compliance with donor required rules and