Globalization is transforming food environments in low- and middle-income countries (LMICs) with implications for diets and nutrition. However, most food-environment assessments were developed for use in high-income countries. We evaluated the suitability of 113 data-collection assessments (i.e., methods, tools, and metrics) for eight dimensions of informal and formal market food environments for diverse contexts of LMICs. We used a scoring exercise and a survey of experts (n = 27). According to the scoring exercise, 10 assessments (8 methods, 1 tool, and 1 metric) were suitable without modification for informal markets. Suitability for formal markets was markedly higher, with 41 assessments (21 methods, 14 tools, and 6 metrics) found suitable without modification. Experts considered availability, accessibility, price, and affordability the most important dimensions of market food environments to evaluate in LMICs. Market-basket analysis and vendor audits (which include inventories) were ranked as the most suitable methods to assess multiple dimensions of market food environments, including availability, price, affordability, vendor and product characteristics, marketing, and regulation. Gaps in relevant assessments were found for convenience and desirability. Results demonstrate the need for the development, adaptation, and validation of assessments relevant for informal markets in a diverse range of LMIC contexts to support diets, nutrition, and health globally.