Profiling the vast diversity of the T-cell repertoire at single-cell resolution is challenging due to the scale and cost requirements involved. Current technologies capture TCR or perform single-cell sequencing at scale but struggle to combine both. The following protocol describes the steps taken to perform REFLEX TCR on the 10x Genomics, GEM-X v1 platform, using cryopreserved human PBMCs as a starting point. With it, one can expect to generate multi-omic profiling inclusive of FLEX transcriptome, paired alpha and beta TCR (paired efficiency varies with sample context), and protein level information through ADTs if desired.