<p>Cash transfers alleviate financial hardship as either conditional programs, requiring behavioral compliance, or unconditional programs. We undertook a systematic review, quality appraisal, and meta-analysis of 16 RCTs following PRISMA guidelines, examining effects of cash transfers on child development among children&#xa0;(<i>n</i> = 29,887, &lt;8 years old) in low- or middle-income countries; papers were excluded if they used quasi-experimental or simulation methods, or did not have a control group without cash. To examine risk of bias in the studies, we used the revised Cochrane risk-of-bias tools for individually randomized trials (RoB 2) and cluster randomized trials (RoB 2 CRT). After 3.6 years, cash transfers had a small but&#xa0;significant positive effect on cognitive (Cohen’s <i>d</i>  =  0.08, 95% CI 0.04, 0.13), language (<i>d</i>  =  0.09, 95% CI 0.04, 0.13), and gross motor outcomes (<i>d</i>  =  0.07, 95% CI 0.03, 0.11); only conditional cash transfers showed significant effects on socio-emotional outcomes (<i>d</i>  =  0.17, 95% CI 0.04, 0.31). Across outcomes, findings were strongest for children in families receiving conditional cash transfers and a sub-set of cash transfer programs (“cash-plus”, which integrated health, nutrition, or&#xa0;parenting support). Limitations of the analysis are that we&#xa0;could only include a small number of studies, and that&#xa0;there was a great degree of heterogeneity among cash transfer programs, and thus our findings are exploratory. In spite of these limitations, our findings suggest that cash transfers were most effective to promote child development when the transfers were bundled with crucial services&#xa0;or support for families, not simply as cash alone.</p>