This study examines macroeconomic indicators to evaluate the performance of Iran’s Twenty-Year Vision Plan, focusing particularly on the factors affecting investment due to its direct relationship with economic growth and inflation. The research covers the period from 2005 to 2023 (1384–1402 in the Iranian calendar) using quarterly data and applies the Autoregressive Distributed Lag (ARDL) model to analyze both short-term and long-term effects on investment. The findings show that in the short run, the current Gross Domestic Product (GDP) does not significantly affect investment. However, the first and second lagged values of GDP have positive and statistically significant effects, indicating that past economic growth positively influences current investment. Inflation has a negative and significant impact on investment in the short term. Specifically, a one percent increase in the Consumer Price Index reduces investment by approximately 0.19 percent. The lending interest rate does not show a significant short-term impact on investment. Additionally, earlier sanctions imposed during 2008–2009 and 2012–2015 do not significantly affect investment. In contrast, the more severe sanctions between 2018 and 2021 have a strong and statistically significant negative impact, demonstrating that recent sanctions acted as a major structural shock to investment. In the long run, GDP has a strong positive and statistically significant effect on investment, indicating that sustained economic growth promotes higher investment levels. Inflation continues to have a significant negative effect on investment over the long term. Although lending interest rates have a negative relationship with investment in the long run, this effect is not statistically significant. Overall, the results highlight the crucial roles of economic growth, inflation control, and external economic shocks in shaping investment trends in Iran.