The Caryophyllaceae (the carnation family) is one of two flowering plant families with a cosmopolitan distribution spanning all seven continents. Previous systematic work on the Caryophyllaceae demonstrated multiple transitions into arctic-alpine climates, indicating that they may provide a natural model for understanding how plants adapt to changing climates. Arctic-alpine is a stressful environment and outside of the optimum temperature range for most angiosperms. Surviving these stressful conditions requires several adaptive changes. Several species within the Caryophyllaceae have converged on the cushion plant adaptation, which is often associated with plants surviving in cold temperatures. Previous research has shown that paleopolyploidy events are correlated with climatic shifts in Caryophyllales. In this study, we investigate whether paleopolyploidy events and gene duplications are associated with arctic-alpine adaptations in the Caryophyllaceae, specifically identifying genes that may have contributed to these processes. Utilizing 26 newly collected transcriptomic data with increased cushion plant sampling, along with 45 previously published transcriptomes, we inferred a species tree for the Caryophyllaceae. The species tree was mostly congruent with the current consensus within the family with the exception of the genus Dianthus (carnations) that had a high level of dominant alternative gene tree conflicts. Additionally, we inferred five new paleopolyploidy events that have not been previously published. Paleopolyploidy events mostly do not directly correspond to a shift to an arctic-alpine climate at the same or adjacent nodes though they are a major source of gene duplications. We identified overlapping gene duplications for arctic-alpine clades, in which some are involved in stress tolerance based upon the GO annotations indicating the potential for convergent evolution in cold-tolerant Caryophyllaceae species. We further explore the correlation between climatic niche shifts and gene duplications in this family and conduct positive selection tests on genes potentially involved in cold adaptation.