Background: Segmentation use in social marketing especially in improving the health of young adults is limited, and theory use within segmentation remains infrequent. A generalisable segmentation structure that can be reliably applied across different young adult’s samples may assist social marketers to move beyond one size fits all healthy eating programs. Focus of the Article: Segmentation is an essential marketing principle which allows customising marketing activities to the needs of specific segments. Evidence shows that behaviour change is more likely when more principles are used, yet segmentation remains underutilised and a cross-sample validation of segments across different populations remains to be demonstrated. Importance to the Social Marketing Field: Delivery of healthy eating programs targeted to group differences and accommodating a broader theory-based socio-ecological viewpoint is needed to engage with a cross section of young adults more effectively along with a cross-sample validation of segments across different populations to identify a valid segmentation structure that can be reliably applied across the Australian young adult population. Methods: A replication study was conducted using the same constructs, items and analytical procedures as in the original study. Data was collected online and in person using a paper survey in two military bases to ensure a mix of Australian Defence Force (ADF) trainee types. Psychographic variables informed by the MOA framework were collected and used to segment the sample with two-step cluster analysis along with a demographic measure (education) and behavioural measure (eating behaviour) to repeat the segmentation analysis. Results: The ability of the MOA framework to explain eating behaviour was confirmed in the ADF trainee sample, and two-step cluster analysis produced a similar segment structure to the original study with education, opportunity and motivation to eat healthy being the most important variables in segment formation. Recommendations for Research or Practice: Segmentation is important for developing understanding that enables social marketers to design social change programs to meet the needs of young adults. This empirical replication study confirmed a similar theory-driven healthy eating segment solution across two young adult populations illustrating the value of using behavioural theories to draw segments and utilising the same theory to cross-validate the constructs in a comparable sample. Future research could use this approach to identify a valid segmentation structure that can be reliably applied across different populations and behavioural contexts.