We conducted a genome-wide association study for testicular germ cell tumor, genotyping 298,782 SNPs in 979 affected individuals and 4,947 controls from the UK and replicating associations in a further 664 cases and 3,456 controls. We identified three new susceptibility loci, two of which include genes that are involved in telomere regulation. We identified two independent signals within the TERT-CLPTM1L locus on chromosome 5, which has previously been associated with multiple other cancers (rs4635969, OR = 1.54, P = 1.14 × 10−23; rs2736100, OR = 1.33, P = 7.55 × 10−15). We also identified a locus on chromosome 12 (rs2900333, OR = 1.27, P = 6.16 × 10−10) that contains ATF7IP, a regulator of TERT expression. Finally, we identified a locus on chromosome 9 (rs755383, OR = 1.37, P = 1.12 × 10−23), containing the sex determination gene DMRT1, which has been linked to teratoma susceptibility in mice.