Background <p>Digital tools are increasingly used to support recruitment and retention of participants in paediatric research, particularly since the COVID-19 pandemic. However, the extent of the evidence supporting this method in paediatric populations has yet to be evaluated. This scoping review aimed to review the literature on digital tools for recruitment and/or retention of participants in paediatric research, including emerging evidence following the pandemic.</p> Methods <p>A scoping review was conducted following Joanna Briggs Institute methodology. We included peer-reviewed quantitative, qualitative, and mixed-method studies evaluating a digital tool for recruitment or retention in paediatric research in any patient population aged &lt;13 years. Records were identified from systematic database searches with a librarian (EMBASE, MEDLINE, CINAHL), limited to English, from 2013 onwards (last search 03/07/2024), and manual searches. Records were screened and extracted independently in duplicate. The data were charted and narratively summarised.</p> Results <p>Sixty-one out of 4988 records were included. Most evaluations used an observational design; only 5 (8%) involved a randomised experiment. The host studies were mostly aiming to recruit children aged 5–12 years (<i>n</i> = 42; 69%), with a predominantly health promotion (<i>n</i> = 18; 30%), developmental (<i>n</i> = 12; 20%), or oncology (<i>n</i> = 9; 15%) focus. Most studies used multi-component digital interventions for recruitment (<i>n</i> = 39/53; 74%) or retention (<i>n</i> = 17/31; 55%). Social media (<i>n</i> = 33/52; 62%) and websites (<i>n</i> = 19/53; 36%) were most commonly used for recruitment, whereas text/instant messaging (<i>n</i> = 17/31; 55%) and email (<i>n</i> = 11/31; 36%) were the most common retention strategies. The estimates of recruitment and retention rates, and reach per digital tool varied widely between studies. Strategies in underserved populations reflected those used most commonly overall. Multi-component digital strategies were found to support a high rate of retention (84.1–90.7%) during pandemic restrictions.</p> Conclusions <p>This scoping review highlights the broad array of digital tools that have been used to support recruitment and retention in studies of infants and children, including in subgroups of underserved populations and in response to the COVID-19 pandemic. Most evaluations were observational and examined&#xa0;multi-component digital interventions. The lack of studies with a robust analytical design in the literature signals a need for further high-quality, randomised, within-study evaluations following standardised reporting criteria.</p> Registration <p>The protocol was registered on the Open Science Framework (OSF) at <a href="https://osf.io/ybfhr/">https://osf.io/ybfhr/</a>. Registered on&#xa0;July 5 2024.</p>