The goal of this study was to look at the factors that influence real estate investment decisions in Zanzibar social security funds (ZSSF). The unit root test, co-integration, and vector error correction model (VECM) were used for estimation in the linear econometric model equation, which looked at four internal factors: member contribution (MC), benefit payment (BP), return on investment (ROI), and investment in government securities (IGS). The estimated result showed that there was presence of long-run relationship at equilibrium between real estate investment decisions (REID) in ZSSF and all tested factors that influence real estate investment decisions in social security funds. The results revealed that member’s contributions (MC), return on investment (ROI) and investment in government securities (IGS) had positive significant long run relationship with real estate investment decisions in ZSSF. But it was further revealed that the benefit payment (BP) had a negative relationship with REID at ZSSF, though they were statistically significant. The study then recommends among others, that management of ZSSF has to consider these factors when they make real estate investment decisions, this including maintaining the share of investment in Government security since it is the only investment avenue which has low risk and it give up predictable and stable return as result it increases real estate investment.