ABSTRACT: Sleep is commonly regarded as a state of disconnection from the environment. Yet, instances of external sensory stimuli affecting the course of dreams have been reported for centuries. Importantly, understanding the impact of external stimuli on dreams could shed light on the origin and generation of dreams, the functional mechanisms that preserve sleep continuity, and the processes that underlie conscious awareness. Moreover, the possibility of using sensory stimuli for dream engineering could potentially benefit patients suffering from alterations in the intensity or content of sleep conscious experiences. Here, we performed a systematic review following PRISMA guidelines to evaluate the robustness of the current evidence regarding the influence of external sensory stimulation during sleep on dreams experiences. In a literature search using PsycNET, PubMed, ScienceDirect, and Scopus, we selected any experimental work presenting dream data obtained from a confirmed sleep episode during which visual, auditory, olfactory, gustatory, or somatosensory stimulation was administered. A methodological assessment of the included studies was performed using an adapted version of the Downs and Black’s (1998) checklist. Fifty-one publications met the inclusion criteria, of which 21 reported data related to auditory stimulation, 10 to somatosensory stimulation, 8 to olfactory stimulation, 4 to visual stimulation, 2 to vestibular stimulation, and 1 to multi-modal stimulation (audio-visual). Furthermore, 9 references involved pre-conditioned associative stimulation procedures: 6 relied on targeted memory reactivation protocols and 3 on targeted lucid reactivation protocols. The reported frequency of stimulus-dependent dream changes across studies ranged from 0% to ~90%. Such a variability likely reflects the considerable heterogeneity of experimental and methodological approaches. Overall, the literature analysis identified a lack of substantial understanding of the key mechanisms, functions, and correlates of stimulus-dependent dream changes. We believe that a paradigm shift is required for meaningful and significant advancement in the field. We hope that this review will serve as a starting point for such a shift. KEYWORDS: sleep, dream, sensory stimulation, incorporation, modulation