Increased neur­al activ­i­ty in left angu­lar gyrus (AG) accom­pa­nies suc­cess­ful com­pre­hen­sion of acousti­cal­ly degrad­ed but high­ly pre­dictable sen­tences, as pre­vi­ous func­tion­al imag­ing stud­ies have shown. How­ev­er, it remains unclear whether the left AG is causal­ly rel­e­vant for the com­pre­hen­sion of degrad­ed speech. Here, we applied tran­sient vir­tu­al lesions to either the left AG or supe­ri­or pari­etal lobe (SPL, as a con­trol area) with repet­i­tive tran­scra­nial mag­net­ic stim­u­la­tion (rTMS) while healthy vol­un­teers lis­tened to and repeat­ed sen­tences with high- vs. low-pre­dictable end­ings and dif­fer­ent noise vocod­ing lev­els. We expect­ed that rTMS of AG should selec­tive­ly mod­u­late the pre­dictabil­i­ty gain (i.e., the com­pre­hen­sion ben­e­fit from sen­tences with high-pre­dictable end­ings) at a medi­um degra­da­tion lev­el. We found that rTMS of AG indeed reduced the pre­dictabil­i­ty gain at a medi­um degra­da­tion lev­el of 4‑band noise vocod­ing (rel­a­tive to con­trol rTMS of SPL). In con­trast, the behav­ioral per­tur­ba­tion induced by rTMS reversed with increased sig­nal qual­i­ty. Hence, at 8‑band noise vocod­ing, rTMS over AG vs. SPL increased the over­all pre­dictabil­i­ty gain. Togeth­er, these results show that the degree of the rTMS inter­fer­ence depend­ed joint­ly on sig­nal qual­i­ty and pre­dictabil­i­ty. Our results pro­vide the first causal evi­dence that the left AG is a crit­i­cal node for facil­i­tat­ing speech com­pre­hen­sion in chal­leng­ing lis­ten­ing conditions.