The current study aimed at investigating the effect of utilizing the Six Thinking Hats strategy on developing the English Language speaking skill and attitudes towards the skill among online EFL General Diploma students. The participants were one experimental group, thirty-two students. Three main instruments were used for data collection: speaking sub-skills checklist, speaking test and attitudes scale. The experimental group were taught using the Six Thinking Hats strategy for twelve weeks during the first semester of the academic year 2020/2021. Data collected through the pre and post administration of the instruments was subjected to t-test. The results, revealed through the post-administration of the speaking test and the attitudes scale, displayed that the post-performance of the experimental group significantly exceeded its own pre-performance. Thus, the results reflected support for the study hypotheses. They proved the positive effect of the Six Thinking Hats strategy on developing the English Language speaking skill and attitudes towards the skill among online EFL General Diploma students.