A number of roller-compacted concrete pavements (RCCP) have been constructed without saw-cut joints in order to save construction cost. Then it will allow natural cracks to randomly occur at the early age after concrete placement. Crack spacing of unjointed RCCP is crucial to ensure an adequate crack width and load transfer across the cracks since large crack spacing will result in excessive crack width and reduce load transfer efficiency that may be cause faulting, excessive deflection, and further cracking in RCCP slab. Due to pavement thickness, climatic condition, and material properties, unjointed RCCP may have different natural crack spacing. In this study, an analytical approach to predict natural crack spacing of an unjointed RCCP was developed. An analytical method based on elastic theory to calculate axial restraint stress using a bilinear slab-subbase interfacial constraint assumption was conducted. Curling stress induced by temperature gradient through the depth of the slab was also considered. The analytical model incorporates the environmental effect, strength gain and modulus of elasticity, coefficient of thermal expansion, drying shrinkage, base type materials, and slab geometries. The predicted crack spacing results obtained from the predictive model were validated through field measured data. The results showed a good agreement compared with crack spacing measured in the field. Furthermore, the result from a sensitive analysis using proposed predictive model showed that crack spacing increased when thickness of RCCP increased. The predicted crack spacing results may be used as input parameters to estimate crack widths in unjointed RCCP under given climatic condition, and material properties. If estimated crack width is excessive and cannot maintain an adequate load transfer across the cracks, saw-cut joints with an appropriate spacing should be provided in order to minimize crack width, and to prevent future cracking of RCCP leading to better performance.