Fracture behavior of porous glass is investigated through a combined finite element-fracture mechanics approach. In contrast to earlier studies, here, simulations embody flaw size distributions in addition to pore-pore stress interactions and crack orientation along pore surfaces. Fracture strength of porous glass shows a steep decrease up to 20% porosity and then levels off due to interacting pores. Weibull modulus varies because of the decreased probability of interactions in microstructures containing less than 2% porosity or the smallest pore diameter =48m. Weibull modulus strongly depends on crack size distributions for porosity less than 2% and pore-pore stress interactions for porosity greater than 5%.