Deciphering the genetic basis of complicated agronomic, yield, biotic and abiotic stress resistance, and quality traits is the principal pursuit of genetics. In the post-genomics era, state-of-the-art techniques like QTL-seq, genotyping by sequencing, and genome-wide association studies (GWAS) have accelerated the identification of QTLs associated with complex traits in crop plants. GWAS utilizes the presence of high recombination in natural populations used for association studies. These innovative tools have also been proved effective in Brassica oleracea vegetables, and numerous sets of QTLs by employing GWAS have been determined. Among the cole group of vegetables, cauliflower (Brassica oleracea var. botrytis L.) predominates in India and globally, being an essential contributor in balanced human diet. The most economic part in cauliflower in curd and understanding of curd complexities based on genomics approaches is of utmost importance for revealing the QTLs regulating curd architecture in cauliflower. GWAS and QTL analysis have been successfully applied in understanding curd-related traits and curd architecture in cauliflower. Different sets of mapping populations like doubled haploid, biparental mapping populations, and natural populations have been proved effective in QTL analysis studies in cauliflower. But as compared to other Brassica oleracea vegetables, limited research has been carried out in determining the QTLs and genetic basis of various quality, biotic stress resistance, and abiotic stress-resistance traits in cauliflower. In this context, the GWAS and QTL-seq can be potentially applied in elucidating complex traits in cauliflower. This chapter summarizes the up-to-date progress made in GWAS and QTL mapping of different traits in cauliflower.