Selain masalah fisik dan teknis, sistem agribisnis tanaman hortikultura sayuran semusim juga di hadapkan dengan permasalahan kelembagaan, tak terkecuali pada kelembagaan agribisnis sayuran semusim di kelurahan kampung enam kecamatan tarakan timur. oleh karenanya, penelitian ini bertujuan untuk: (1) mengidentifikasi lembaga dan peran lembaga pada sistem agribisnis hortikultura sayuran semusim di kelurahan kampung enam; dan (2) mendeskripsikan model kelembagaan pada sistem agribisnis hortikultura sayuran semusim di kelurahan kampung enam. data yang digunakan terdiri atas data primer dan data sekunder, sedangkan metode analisis yang digunakan adalah analisis deskriptif kualitatif. hasil penelitian menunjukkan bahwa: (1) peran setiap lembaga pada sistem agribisnis hortikultura sayuran semusim di kelurahan kampung enam, yaitu: (a) subsistem hulu lembaganya adalah kios sipakainge dan toko esa; (b) subsistem usahatani lembaganya adalah kelompok tani sinar anugrah, kelompok tani sinar berkat, kelompok tani sinar karya, dan kelompok tani sinar harapan ; (c) subsistem pemasaran lembaganya adalah asosiasi meja pasar petani bukit amal dan (d) subsistem jasa penunjang lembaganya adalah dinas ketahan pangan dan pertanian kota tarakan, balai penyuluhan pertanian kota tarakan, lkm-a petani bukit amal, dan gapoktan bukit amal; dan (2) model kelembagaan sistem agribisnis hortikultura sayuran semusim di kelurahan kampung enam yang terdiri atas kelembagaan subsistem hulu, kelembagaan subsistem on farm, kelembagaan subsistem pemasaran dan kelembagaan subsistem jasa penunjang. dimana pada setiap kelembagaan terdapat pihak atau lembaga yang berperan didalamnya, serta memiliki hubungan erat satu sama lain terutama pada lembaga subsistem jasa penunjang yang berperan penting dalam mendukung dari subsistem hulu hingga hilir. kata kunci: sayuran semusim, sistem agribisnis, peran lembaga, model kelembagaan

In addition to the physical problems that occurred in the ups and downs of the production of seasonal vegetable crops, there were also institutional issues that affected the quality of the crops. this was the case in kampung enam urban village, east tarakan sub-district. the objectives of this research were: (1) to identify the institutions and the roles of the institution in the seasonal vegetable horticulture agribusiness system in kampung enam urban village, (2) to describe the institutional models of the seasonal vegetable horticulture agribusiness system in kampung enam urban village. through a descriptive qualitative method, this research revealed that, first, the roles of various institutions in the establishment and operation of the agribusiness system for seasonal vegetable horticulture in kampung enam urban village, namely: (a) the main sub-system that served as the upstream component was the esa shop and sipakainge stall. they were responsible for providing the farmers with the necessary infrastructure (sarprodi) and equipment (alsintan) to improve their agricultural productivity; (b) the subsystem components of the vegetable production were identified sinar anugrah farmers group, sinar berkat farmers group, sinar karya farmers group, and sinar harapan farmers group. these institutions were responsible for the welfare of the farmers; (c) the marketing subsystem was handled by meja pasar petani bukit amal association which was an alternative forum for marketing crops; (d) the other sub-systems that served as the supporting service the agriculture and food service office of tarakan city, lkm-a of the bukit amal farmers, and gapoktan of bukit amal. these institutions were involved in the distribution of saprodi, alsintan, the establishment of farming capital, and the extension activities to improve the human resource capacity of farmers. second, the institutional models of the seasonal vegetable horticulture agribusiness system in kampung enam urban village consisted of upstream subsystem institution, on farm subsystem institution, marketing subsystem institution, and support services subsystem institution. in each institutional subsystem from upstream to downstream, there were parties or institutions that play their roles and had close relationships with each other, especially in supporting service subsystem institutions that played an important role in supporting the upstream to downstream subsystems. keywords: seasonal vegetables, agribusiness system, role of institution, institutional model