The 2021 Women's National League, known as the SSE Airtricity WNL for sponsorship reasons, is the 11th season of the Women's National League, the highest women's association football league in the Republic of Ireland since its establishment in 2011. Peamount United were the defending champions, having won their third league title the previous season. The 1,007 spectators at Cork City's 3–1 win over Treaty United on 6 November 2021 at Turners Cross set a new WNL record for the highest attendance.