Lyophilization maximises vaccines’ stability, shelf life; maintains chemical or biological functions; enables easier transportation and storage compared to a cold chain. Success of vesicular stomatitis virus (VSV) based vaccines has been highlighted by its increased adoption by pharmaceutical companies and most importantly, the recently approved vaccine for high consequence Ebola virus (EBOV). Lujo virus (LUJV) and Lassa virus (LASV), both arenaviruses, are still without licensed vaccines, however, researchers are exploring VSV-vectored vaccines. Many of these highly pathogenic viruses are endemic in tropical regions like Africa where slight breach in cold chain may affect stability of vaccines. It was established that slight changes in cold chain conditions do not affect efficacy of VSV-based vaccines, however, it is imperative to optimise thermostability of VSV-based vaccines using lyophilization. The primary hypothesis of this study is that lyophilized VSV-LASV and VSV-EBOV vaccines exposed to sub-optimal temperature will retain infectivity in cell culture and protect against LASV challenge in inbred Hartley guinea pigs. Different combinations of commercially available stabilisers were used to assess the thermostability of VSV-based vaccines at 4, 21 and 37 °C of storage temperatures. Lyophilized VSV-LASV and VSV-EBOV were recoverable in Vero cells, the recovery titer showed an inverse relationship with exposed temperature and duration of storage of 1, 7, 35 and 90 days. Furthermore, lyophilized VSV-LASV affords 100% protection and sterilising immunity against LASV infection in inbred Hartley guinea pigs.