Electromagnetic form factors allow to investigate fundamental properties of the baryons.
The BESIII collaboration has studied the time-like form factors of the proton and neutron with significantly improved precision. An intriguing periodic behavior of effective form factors lineshape is observed for both proton and neutron. Hyperons provide a unique avenue to study the strong interaction in baryon structure. Due to the unstable nature of hyperon, their form factors are usually studied in time-like via e+e- annihilations experiments. With the unique data sets obtained by the BESIII collaboration, the pair production cross sections for Lambda, Sigma, Xi, and Lambda_c are studied from threshold, where some abnormal threshold effects are observed. Using the self-analyzing weak decays of the Lambda and Lambda_c, the relative phase between the electric and magnetic form factors is measured. In this presentation the latest results on baryon form factors at BESIII are discussed.