Pengembangan budidaya ikan nila memberikan manfaat bagi masyarakat pedesaan berupa lapangan kerja, dan sumber pendapatan masyarakat. Namun variabilitas dan perubahan iklim ditengarai sebagai salah satu faktor penyebab kematian massal ikan yang menyebabkan kerugian ekonomi, sosial dan lingkungan. Cuaca ekstrem bisa lebih berbahaya bagi ikan nila keramba jaring apung di Waduk Gajah Mungkur. Studi ini bertujuan untuk mengungkapkan kerentanan penghidupan pembudidaya ikan nila keramba jaring apung di Waduk Gajah Mungkur. Pengumpulan data dilakukan dengan pendekatan metode campuran seperti survei, wawancara mendalam, diskusi kelompok terfokus dan observasi. Unit analisis data dilakukan di tingkat rumah tangga dengan melibatkan empat puluh pembudi daya skala kecil. Indeks Kerentanan Mata Pencaharian (LVI) berdasarkan Intergovernmental Panel Climate Change (IPCC) digunakan untuk analisis data. Hasil penelitian menunjukkan bahwa tingkat kerentanan penghidupan pembudidaya ikan nila sakal kecil pada keramba jaring apung berdasarkan LVI-IPCC dapat dikategorikan tidak rentan dengan nilai indeks 0,042. Oleh karena itu, penghidupan pembudi daya ikan nila keramba jaring apung di Waduk Gajah Mungkur ,Wonogiri ini dinilai cukup tangguh. Adaptasi yang dilakukan pembudidaya di antaranya adaptasi sosial melalui kuatnya hubungan sosial antar komunitas pembudidaya ikan dan tingginya partisipasi dalam keanggotaan kelompok sosial. Adaptasi teknologi dan ekologi melalui inovasi yang dikembangkan oleh setiap pembudidaya ikan seperti menggunakan mesin diesel untuk meningkatkan kadar oksigen, dan mengurangi jumlah plot saat perubahan musim serta mengontrol jumlah benih. Meskipun indeks tingkat kerentanan pembudi daya ikan nila keramba jaring apung di Waduk Gajah Mungkur Wonogiri dikatakan tidak rentan, masih diperlukan adanya program pemberdayaan SDM untuk meningkatkan sistem penghidupan yang berkelanjutan.Title: Livelihood Vulnerabiliy Index of Small Scale Tilapia Fish Farmer Floating Net Cages in the Gajah Mungkur Reservoir, Wonogiri RegencyThe development of tilapia aquaculture provides benefits for rural communities in the form of employment and source of income community. However, the variability and climate change are suspected as one of the factors causing mass fish mortality which causes economic, social and environmental losses. Extreme weather can be more dangerous for floating net cages in the Gajah Mungkur Reservoir. This study reveals the vulnerability of the livelihoods of floating net cages in the Gajah Mungkur Reservoir. Data Collected used method is a mixed methods approach such as surveys, in-depth interviews, focus group discussions and observations used to collect data. Unit analysis was carried out at the household level involving 40 small-scale farmers. The Livelihood Vulnerability Index (LVI) based on the Intergovernmental Panel Climate Change (IPCC) was used for data analysis. The results showed that the level of vulnerability of small-scale tilapia cultivators in floating net cages based on LVI-IPCC can be categorized as ‘not vulnerable’ with an index value of 0.042. Therefore, the livelihood of this floating net cage tilapia fish farmers in the Gajah Mungkur Wonogiri Reservoir is considered quite tough. Adaptations that are carried out by fish farmers include social adaptation through strong social relationships between fish farmer communities and high participation in social group membership. Technology and ecological adaptation through innovations developed by each fish farmer such as using a diesel engine to increase oxygen levels, and reduce the number of plots when the seasons change and control the number of seeds. Although the vulnerability index of floating net tilapia cultivators in the Gajah Mungkur Wonogiri Reservoir is said to be not vulnerable, it is still necessary to have a human resource empowerment program to improve a sustainable livelihood system.