Numerous long non-coding (lnc) RNAs are highly enriched or exclusively expressed in the mammalian testis, even in spermatids. Spermatid perinuclear RNA-binding protein (STRBP) can bind many RNAs, and loss of STRBP impairs male fertility. However, the functions of lncRNAs interacting with STRBP are unknown. In this study, the roles of one STRBP-interacting lncRNA, namely predicted gene 31453 (Gm31453), and its potential target gene encoding carboxypeptidase A5 (Cpa5) in spermatogenesis were determined using gene-knockout (KO) mice. Gm31453 and Cpa5 are located adjacent to each other on the same chromosome and are highly expressed in the testis. Gm31453 and Cpa5 are primarily expressed from secondary spermatocytes to elongated spermatids, implying their involvement in spermiogenesis. Although deletion of Gm31453 disturbed the expression of both its target and interacting gene, as indicated by decreased Cpa5 and increased Strbp mRNA levels, both Gm31453- and Cpa5-KO mice showed normal spermatogenesis and fertility, and had no detectable abnormalities in terms of testicular and epididymal development, sperm production morphology or motility, pregnancy rate or litter size. Thus, Gm31453 and Cpa5 are dispensable for spermatogenesis and male fertility in mice. Their involvement in spermatogenesis may be a fine-tuning role, regulating gene expression at the molecular level.