The 21st Century workforce must be flexible, adaptable, and innovative to stay competitive in today's fast-paced, ever-changing job market. Organizations play an important role in supporting the professional growth of its employees by offering various kinds of formal and informal professional development opportunities. While formal learning may be beneficial to individual employees, the learning that takes place within these structured training programs is not always disseminated to other members within the organization. If organizations create more informal adult learning opportunities, with an emphasis on workplace learning, then the transfer of knowledge between individuals within the organization might increase thus broadening employees' knowledge, skills, and conceptual understanding in the workplace context. Therefore, the purpose of this doctoral thesis was to explore informal adult learning in the workplace as a potentially untapped mode of professional development in organizations. Using the more knowledgeable other (MKO) and zone of proximal development (ZPD) from Lev Vygotsky's Sociocultural Theory as the theoretical framework, this Interpretive Phenomenological Analysis (IPA) study sought out to answer the following research question: "What are the experiences of newly, internally-promoted leaders of a K-12 private, non-profit, co-educational, bilingual school in Jordan; and how do they make sense of their firsthand experience with informal adult learning interactions as a mode of professional development in the workplace?" The study provided a platform for five participants to share their reflections from their learning experiences during a critical transition time in their professional careers. Their personal recounts with regard to seeking support from colleagues, as well as them assuming the role as supporters for their colleagues identified that an individual's attitude towards learning determines if, when, how frequently, with whom and to what extent she engages in learning. A positive, harmoniously ethos where individuals demonstrate mutual respect, trustworthiness, and intercultural understanding creates a workplace conducive for learning to take place. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]