Purpose: We aimed to systematically identify and characterize existing digital health tools for pain monitoring in children with cancer, and to assess common barriers and facilitators of implementation. Methods: A comprehensive literature search (PubMed, Cochrane, Embase, and PsycINFO) was carried out to identify published research on mobile apps and wearable devices focusing on acute and/or chronic pain in children (0–18 years) with cancer (all diagnoses) during active treatment. Tools had to at least include a monitoring feature for one or more pain characteristic(s) (e.g., presence, severity, perceived cause interference with daily life). Project leaders of identified tools were invited for an interview on barriers and facilitators. Results: Of 121 potential publications, 33 met inclusion criteria, describing 14 tools. Two methods of delivery were used: apps (n=13), and a wearable wristband (n=1). Most publications focused on feasibility and acceptability. Results of interviews with project leaders (100% response rate), reveal that most barriers to implementation were identified in the organizational context (47% of barriers), with financial resources and insufficient time available mentioned most often. Most factors that facilitated implementation related to end users (56% of facilitators), with end-user cooperation and end-user satisfaction mentioned most often. Conclusions: Existing digital tools for pain in children with cancer were mostly apps directed at pain severity monitoring and little is still known about their effectiveness. Paying attention to common barriers and facilitators, especially taking into account realistic funding expectations and involving end users during early stages of new projects, might prevent evidence based interventions from ending up unused.