High‐throughput techniques have identified numerous antisense (AS) transcripts and long non‐coding RNAs (ncRNAs). However, their significance in cancer biology remains largely unknown. Here, we report an androgen‐responsive long ncRNA, CTBP1‐AS, located in the AS region of C‐terminal binding protein 1 (CTBP1), which is a corepressor for androgen receptor. CTBP1‐AS is predominantly localized in the nucleus and its expression is generally upregulated in prostate cancer. CTBP1‐AS promotes both hormone‐dependent and castration‐resistant tumour growth. Mechanistically, CTBP1‐AS directly represses CTBP1 expression by recruiting the RNA‐binding transcriptional repressor PSF together with histone deacetylases. CTBP1‐AS also exhibits global androgen‐dependent functions by inhibiting tumour‐suppressor genes via the PSF‐dependent mechanism thus promoting cell cycle progression. Our findings provide new insights into the functions of ncRNAs that directly contribute to prostate cancer progression.