Purpose <p>Assessing differences between lived experiences of people affected by cancer internationally facilitates direction of international health policies and standards. The study piloted, on behalf of the World Health Organization (WHO), a global survey assessing the lived experience of people affected by cancer. We aimed to determine (1) the acceptability of the survey and (2) the survey’s capacity to capture a globally representative sample of people diagnosed with cancer.</p> Methods <p>The cross-sectional survey went through two pilot rounds. We (1) solicited feedback from international cancer organisations through a feedback form, and (2) launched a global online survey, requesting open-ended feedback on the survey format/content from people diagnosed with cancer, their family members/caregivers, and bereaved family members.</p> Results <p><i>Round one</i>: 23 stakeholders found the survey acceptable in length/content. Minor suggestions were to improve readability/applicability across healthcare settings. <i>Round two</i>: 505 individuals participated: 177 (35%) provided feedback on the study design (e.g. to include people currently being treated for cancer, and siblings) or survey (e.g. assessing impacts of multiple cancers). Participants seemed to value the opportunity to share their experiences: “Thanks…felt good to answer as if someone was listening.” Compared with global statistics, our sample of people diagnosed with cancer (<i>N</i> = 240) included significantly more females (<i>p</i> &lt; 0.001) and individuals from high-income countries (<i>p</i> &lt; 0.001).</p> Conclusion <p>Participant feedback informed important changes to the survey design and content. Our findings highlight that engaging with people with lived experience is a critical first step to develop such a global survey, optimise participation, and amplify individuals’ voices.</p>