Harmonization of outcomes to be measured in clinical trials can reduce research waste and enhance research translation. One of the ways to standardize measurement is through development and use of core outcome sets (COS). There is limited involvement of low- and middle-income country (LMIC) stakeholders in COS development and use. This study explores the level of awareness and experiences of LMIC stakeholders in the development and use of COS. We conducted an online survey of LMIC stakeholders. Three existing COS (pre-eclampsia, COVID-19, palliative care) were presented as case scenarios, and respondents asked to state (with reason(s)) if they would or would not use the COS if they were working in that area. Quantitative data were analyzed descriptively while qualitative data were analyzed thematically. Of 81 respondents, 26 had COS experience, 9 of whom had been involved in COS development. Personal research interests and prevalence of disease are key drivers for initiation/participation in a given COS project. Most respondents would use the COS for pre-eclampsia (18/26) and COVID-19 (19/26) since the development process included key stakeholders. More than half of the respondents were not sure or would not use the palliative care COS as they felt stakeholder engagement was limited and it was developed for a different resource setting. Respondents reported that use of COS can be limited by (i) feasibility of measuring the outcomes in the COS, (ii) knowledge on the usefulness and availability of COS and (iii) lack of wide stakeholder engagement in the COS development process including having patients and carers in the development process. To ensure the development and use of COS in LMICs, collaborations are essential in awareness raising on COS utility, training, and COS development. The COS also needs to be made accessible in locally understandable languages and feasible to measure in LMICs.