The purpose of this study was to examine the efficacy of some proposed activities for developing creative thinking of English learners at the preparatory stage. The current study adopted the quasi- experimental design. Two groups of English learners were randomly chosen from one of Port- Said governmental preparatory schools. The experimental group received training through the proposed activities; the control group did not receive any training. Creative thinking and academic achievement tests were developed and used as pre and post-tests. The proposed activities were developed by the researcher based on five strategies: brainstorming, attribute listing, morphological synthesis, SCAMPER and CoRT for developing creative thinking. The proposed activities were taught over a period of 10 weeks. Results indicated that the proposed activities increased students' creative thinking abilities (fluency, flexibility, originality and elaboration) and academic achievement. Results showed that the proposed activities based on divergent thinking strategies were effective in improving English learners' creative thinking at the preparatory. It was recommended that a) The present proposed activities can be adopted for developing creative thinking for students at different levels of education b) English teachers should use different divergent strategies and activities to help learners become creative persons, and c) developing creative thinking has to be given more consideration in designing ELT textbooks. .