AbstractWe investigate void properties inf(R)models using N-body simulations, focusing on their differences from General Relativity (GR) and their detectability. In the Hu-Sawickif(R)modified gravity (MG) models, the halo number density profiles of voids are not distinguishable from GR. In contrast, the samef(R)voids are more empty of dark matter, and their profiles are steeper. This can in principle be observed by weak gravitational lensing of voids, for which the combination of a spectroscopic redshift and a lensing photometric redshift survey over the same sky is required. Neglecting the lensing shape noise, thef(R)model parameter amplitudesfR0=10^-5and 10^-4may be distinguished from GR using the lensing tangential shear signal around voids by 4 and 8 σ for a volume of 1 (Gpc/h)³. The line-of-sight projection of large-scale structure is the main systematics that limits the significance of this signal for the near future wide angle and deep lensing surveys. For this reason, it is challenging to distinguishfR0=10^-6from GR. We expect that this can be overcome with larger volume. The halo void abundance being smaller and the steepening of dark matter void profiles inf(R)models are unique features that can be combined to break the degeneracy betweenfR0and σ8.