A teacher training program, named Model-Supported Scientific Inquiry Training Program (MSSITP) has been successfully developed to improve the inquiry skills of Indonesian elementary teachers. The skills enhanced by MSSITP are defining problems, formulating hypotheses, planning and doing investigations, drawing conclusions, and communicating the results. This teacher training program was evaluated by 48 teachers selected by stratified random sampling technique from 48 elementary schools in Bandar Lampung City, Lampung Province, Indonesia. The program was designed to follow Bandura's stages of social learning: attention, retention, production, and motivation. The impact of MSSITP was evaluated in three ways. "First," by analyzing the improvements of inquiry skills compared to conventional SITP through pretest and posttest control group design. "Second," by using an inquiry questionnaire to describe teachers' perceptions of inquiry learning. "Last," by using a response instrument to elicit teachers' opinions of the program. The results indicate a significant difference (sig 0.00) in teachers' skills acquired from the two different training programs. Mean posttest scores, varying from 34.7 to 56.9 for the control group and 58.3 to 98.6 for the experimental group, confirmed the effectiveness of MSSITP.