The 2005 Sultan Qaboos Cup was the 33rd edition of the Sultan Qaboos Cup (Arabic: كأس السلطان قابوس), the premier knockout tournament for football teams in Oman.
The competition began on 1 September 2005 with the Group Stage and concluded on 14 November 2005. Dhofar S.C.S.C. were the defending champions, having won their sixth title in 2004. On Monday 14 November 2005, Al-Nasr S.C.S.C. were crowned the champions of the 2005 Sultan Qaboos Cup when they defeated Al-Seeb Club 3-1, hence winning the title for the fourth time.
16 teams played a knockout tie. 8 ties were played over one leg. The first match was played between Dhofar S.C.S.C. and Sur SC on 6 October 2005. 8 teams advanced to the Quarterfinals.
8 teams played a knockout tie. 4 ties were played over one leg. The first match was played between Sur SC and Al-Tali'aa SC on 13 October 2005. Sur SC, Al-Oruba SC, Al-Nasr S.C.S.C. and Al-Seeb Club qualified for the Semifinals.
4 teams played a knockout tie. 2 ties were played over two legs. The first match was played between Sur SC and Al-Seeb Club on 20 October 2005. Al-Nasr S.C.S.C. and Al-Seeb Club qualified for the Finals.