Developing Primary School Teachers’ English Vocabulary Teaching Using Online Multimedia-Based Instruction

English vocabulary is very crucial for a second or foreign language learner taking into account that a student's ability to communicate in English depends on a total number of words they know. According to the results of previous studies, teaching English vocabulary to young students in primary schools may be facilitated by utilizing online game-based and multimedia-based learning that provides a 21st-century learning environment. However, there is little evidence to support the effectiveness of these two vocabulary teaching methods in EFL Thai context. As a result, this study sought to upper English elementary teachers' satisfaction with vocabulary teaching training through Online Multimedia-Based Vocabulary Instruction for enhancing English vocabulary learning. It also looked at the effectiveness of vocabulary teaching strategies on the sixth-grade students' vocabulary learning in a primary school and their attitude towards the use of Online Multimedia-Based Vocabulary Instruction. The research was a quasi-experimental research with a pretest-posttest control group design and used a mixed-methods approach. Two classes, totally 60 grade six students were selected from three classes, and 30 students were randomly assigned in the experimental group learning through Online Multimedia-Based Vocabulary Instruction, and 30 students in the control group learning by Traditional-Based Vocabulary Instruction. The results showed that teachers' satisfaction with the vocabulary teaching strategies training was very high. Most of teachers perceived the training as a powerful tool for enhancing grade six students’ vocabulary. Statistically significant difference was not found between the English vocabulary posttest of the experimental group and control group, but the experimental group had the positive attitude towards vocabulary learning. The findings implied that Online Multimedia-Based Vocabulary Instruction is an effective technique for developing students’ English vocabulary, specifically at the primary school level. This teaching technique could be applied to the EFL English classroom so that students become achieve their learning goal.