Given the calls to reinforce the accountability of education programmes, this review evaluated studies that evaluated K-12 global citizenship education (GCED) programmes to assess the evidence that such programmes improved the students' global learning. There are no current reviews assessing the impact of GCED programmes in the US. The authors conducted an electronic search in the educational databases to review the studies that addressed the impact of GCED programmes between 2000 and 2019. We reviewed the abstracts based on specific criteria: 33 studies met the inclusion criteria. Most of the studies were rejected because they did not provide the whole information about the programmes. The final 22 studies were selected because they provided the complete description about the evaluation programme of GCED. The review examined the components and the measures of the programmes, the approaches for collecting and analyzing data. The outcomes of the evaluated programmes support the claim that these programmes succeeded in improving students' global learning. However, our analysis revealed flaws in the studies evaluating the impact of the GCED programmes.