The paper examined the essence of women in Mainstreaming Peace and Security in South Sudan by exploring lessons Learned and Way forward. The study has assessed some instruments used in support of UN Resolution 1325 to empower women in promoting peace and security within the country. The paper has examined UNSCR 1325 by understanding the essence of women participation, the execution of the resolution by developing the policy framework, and understanding the avenues applied by women to participate in peace and security in South Sudan. The paper has found out that, R–ARCSS is a great opportunity South Sudan’s gender mainstreaming by complying with UN resolution 1325. The purpose of this study was to articulate the desired end state of Women in Mainstreaming Peace and Security in South Sudan: Lessons Learnt and way forward to serve as a platform for discussions at the highest level of decision–making and to provide a guide for further detailed planning in achieving gender mainstreaming within South Sudan.