The article reviews recent evidence from human neurophysiological studies demonstrating that top-down modulation serves as a common neural mechanism underlying selective attention and working memory (WM) performance. Top-down modulation involves activity modulation in stimulus-selective sensory cortices, concurrent engagement of prefrontal and parietal control regions, and the generation of top-down signals. This mechanism is engaged during both stimulus-present and stimulus-absent stages of WM tasks, including expectation, encoding, maintenance, and retrieval. The review highlights how top-down modulation influences multiple stages of representations that support WM performance, similar to its role in perceptual tasks. Recent studies using fMRI, EEG, and rTMS have provided causal evidence for the role of top-down modulation in WM, showing that it dynamically regulates neuronal excitability to optimize WM performance. The article concludes by discussing the implications of these findings for understanding the relationship between attention and WM, and suggests future research directions, including the role of oscillations in top-down modulation and the potential for enhancing cognitive development through improved focus and selective attention within WM.The article reviews recent evidence from human neurophysiological studies demonstrating that top-down modulation serves as a common neural mechanism underlying selective attention and working memory (WM) performance. Top-down modulation involves activity modulation in stimulus-selective sensory cortices, concurrent engagement of prefrontal and parietal control regions, and the generation of top-down signals. This mechanism is engaged during both stimulus-present and stimulus-absent stages of WM tasks, including expectation, encoding, maintenance, and retrieval. The review highlights how top-down modulation influences multiple stages of representations that support WM performance, similar to its role in perceptual tasks. Recent studies using fMRI, EEG, and rTMS have provided causal evidence for the role of top-down modulation in WM, showing that it dynamically regulates neuronal excitability to optimize WM performance. The article concludes by discussing the implications of these findings for understanding the relationship between attention and WM, and suggests future research directions, including the role of oscillations in top-down modulation and the potential for enhancing cognitive development through improved focus and selective attention within WM.