B Background: Cephalometry analysis is one of the important roles in the diagnosisand treatment plan in the field of orthodontics. One of cephalometric analysis is theTweed triangle analysis consisting of Frankfort Mandibular Angle (FMA) angles,Frankfort Mandibular Incisor Angle (FMIA), and Incisor Mandibular Plane Angle(IMPA). Tweed developed an analysis to assist in treatment planning, preparationfor anchoring, and determine the prognosis of a malocclusion case. Purpose: Tofind out the description of the measurement value of Tweed triangle analysis inorthodontic patients aged 9-12 years RSGM FKG Usakti. Method: This type ofresearch is a descriptive observational cross-sectional design. This sample is takenfrom secondary data, which are cephalograms from orthodontic patients at RSGMFKG Usakti in January to December 2018. This research was conducted bymeasuring 3 parameters based on Tweed analysis. Results: Based on the Tweedtriangle analysis research, the average value of the Frankfort Mandibular Angle(FMA) angle is 32.78°; Frankfort Mandibular Incisor Angle (FMIA) 53.43°; andIncisor Mandibular Plane Angle (IMPA) 88,45°. Conclusion: The average valueof the Tweed triangle analysis with an FMA angle of 32.78°, an FMIA angle of53.43°, and IMPA angle of 88,45°. Most orthodontic patients age 9-12 years atRSGM FKG Usakti have a convex profile and the lower incisors were proclinated.