The present study seeks to identify teachers' perceptions regarding STEM teaching professional development and to identify the factors that facilitate or hinder the success of teachers' professional development. The participants of the study were 35 teachers. A qualitative approach was used for data collection by conducting semi-structured interviews with 11 teachers out of 35. All the participants were involved in the three focus group sessions. The findings of the study revealed that teachers have various perceptions toward the STEM professional development based on their experience, knowledge, and skills. Moreover, the study revealed different factors influencing STEM professional development among teachers including personal characteristics and internal factors including attitudes and beliefs toward STEM professional development activities, and teachers' capacity. Also, external factors such as design of the training program, availability of training material, and timing of training. The findings of the study could benefit the decision-makers to be aware about these factors that influence professional development and the teachers' needs.