The study on the comparative evaluation of the environmental impacts assessment’s signficance in Zambia, South Africa and Zimbabwe’s economic development was conducted in order to demystify mixed insights among Zimbabwean Environmental Impact Assessment (EIA) interested parties regarding its importance and to develop an EIA cost estimation model. This study had significant impact on EIA interested parties in terms of reshaping their EIA perceptions. All these stakeholders had varying concerns regarding EIA costs, delays in projects implementation and the impact on economic growth. The motive for this investigation was to explore the association amid environmental impact assessment and economic growth in Zimbabwe using mixed research method since multinational financiers now requires environmental social safeguards in their project financing criteria. The researcher used stratified random sampling to choose Zambia and South Africa from (Southern African Development Community) SADC which took part in the study with snowball sampling used to select actual participants. Zimbabwe was purposively sampled since it was the epicentre of the study and participants were chosen randomly. Mixed methods were adopted in the study. A case study plan was then applied making use of interviews, focus group deliberations and an electronic questionnaire supported by Kobo toolbox survey platform to collect primary data in the face of Covid – 19 lockdown restrictions. SPSS, Microsoft Excel and Framework Analysis Method were used for data analysis with One – Sample Chi Square testing conducted at 95% significance level. The study established that EIA costs in Zimbabwe were the cheapest in all five economic sectors under investigation and the EIA review periods were the shortest. As such in was concluded that the EIA process in Zimbabwe had no effect on FDI inflows and economic development. Furthermore, the researcher developed the Sunny’s EIA Cost Estimation Model which can be used by EIA practioners for EIA costing though there is need for further studies to refine it.