Performance on visual-verbal tasks is generally impaired by task-irrelevant background speech, which can have consequences for individuals who works in noisy environments (e.g., schools or offices). This study examined the role increased task difficulty plays in shielding against the effects of background speech. This issue was addressed across 4 experiments whereby the level of task difficulty on visual-verbal tasks was manipulated (e.g., by changing the font of a text to one that is harder to read). Experiments 1 to 3 qualified the general finding: that background speech impairs performance on visual-verbal tasks (proofreading and prose memory), but only when task difficulty was low, not when it was high. Moreover, experiment 4 demonstrates that higher task difficulty on the focal task (n-back) also reduces recall on a surprise memory test on the content of a to-be-ignored background story. These results suggest that an increase in task difficulty, which promotes greater task engagement, can shield against the detrimental effects of background speech and also constrain the processing of complex semantic information present in background speech.