Improving the seed protein concentration (SPC) of pea is an important breeding objective because of its underlying nutritional value and the demand from the international processing industries. To understand the genetic control of SPC and support the marker-assisted selection (MAS), we explored three recombinant inbred line (RIL) populations and a genome-wide association study panel (GWAS-2) to identify the quantitative trait loci (QTLs) associated with protein content. The RIL populations used, CDC Amarillo x CDC Limerick (PR-25), MP 1918 x P0540-91 (PR-30), and Ballet x Cameor (PR-31), represent moderate SPC x high SPC crosses. The GWAS-2 panel comprised of representative accessions from global pea breeding programs, pea core germplasm, and commercial cultivars released in Canada. One hundred and ten, and 169 RILs of PR-25 and PR-30, and 233 accessions of GWAS panel were genotyped using a Axiom® 90K SNP array. PR-31 was earlier genotyped using the Genopea 13.2K SNP array [1], and the reported linkage map was used in the current study. Individuals of each mapping population were grown in replicated trials at two to three locations in Saskatchewan between 2019 and 2021. All mapping populations were tested in 5 to 7 station-years. Seed samples harvested from each plot were used for the determination of SPC using near-infrared (NIR) spectroscopy. We identified three QTLs each in PR-25 [2] and PR-30, and five QTLs in PR-31 associated with SPC. The LOD value of the identified QTLs ranged from 3.0 – 11.0. The QTLs from the biparental populations will be compared with those identified in the GWAS and with the published literatures. The highly significant QTLs identified in this study are useful for MAS of pea breeding lines for SPC