In English as a lingua franca (ELF) communication, in which English is used as a common language among interlocutors of different first languages, successful communication often features communication strategies that enhance mutual understanding and relationship management. Although prior research suggests that including such strategies in English language instruction could be beneficial for intercultural communication in English, few empirical studies have investigated the effects of ELF strategy instruction. The unfortunate result is a lack of evidence-based guidance for practitioners who may wish to include communication strategies in ELF-informed instruction as a means of meeting their learners' real-world communicative needs. This dissertation study developed and investigated the effectiveness of instructional materials and assessment instruments for teaching six communication strategies that have been reported in ELF descriptive literature. This sequential mixed-methods study employed a quasi-experimental design to examine the effects of the pedagogical intervention. Forty-three users of ELF for academic purposes (ELFA) at a university in Kuala Lumpur, Malaysia, participated in the study--28 experienced the intervention and 15 acted as a control group. Effects were measured in terms of participants' ability to identify and understand communication strategies in discourse (receptive skills), their overall ELF communicative competence including the use of communication strategies (productive skills), attitudes towards ELF and standardized Englishes, and self-reported transfer of communication strategy learning to authentic communication outside the classroom after the intervention. The results of three pre-posttests demonstrated significant improvement in the experimental group's receptive skills, some improvement of productive skills among experimental participants with low productive pretest scores, and no meaningful changes in language attitudes. Two participants who demonstrated large gains on the receptive posttest were interviewed to explore their self-reported transference of strategy learning to their real-life communication. The interviews revealed inconsistent transfer and complex relationships among their perceptions of ELF communication strategies, attitudes towards ELF and standardized Englishes, relationships with different interlocutors, including the cultural background of the interlocutors, and their transfer of strategy learning. The findings provide guidance for instructors, curriculum developers, and test designers who aim to provide ELF-informed instruction. The findings also highlight important directions for future research in this area. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]