Teaching English as a second or foreign language (ESL/EFL) is not the easiest task for any educator. Even more complicated the task becomes when a teacher has students of two different proficiency levels in one classroom. One of the problems is that weaker students may feel uncomfortable having to study with more proficient in English ones. Therefore, one the teacher’s tasks is to make sure they are treated equally, and provided with all the needed support and encouragement in accordance with their learning needs. Another problem here is that stronger students may, on the contrary, be frustrated due to the need to study together with those, whose skills are not as good. That is why it is necessary to provide them with a wide range of opportunities to further improve and develop the previously acquired skills, as well as acquire and perfect new ones. So, first of all, a teacher must ensure that all the classroom students feel comfortable and secure in the given learning environment in order for their learning to be effective and productive. Successful teaching in such a case entails efficient differentiation of instructions, first of all. That is, weaker students should get easier, corresponding to their proficiency level, tasks to complete, so that they don’t loose confidence in own abilities. In such a way, they will feel comfortable with the learning process. Besides, performing tasks corresponding to their level, and based on the knowledge and skills they acquired before, will ensure that there will be no gaps in their learning process, that it is being conducted gradually and consistently. This, of course, is related to the stronger students as well. Differentiated instructions tasks may include large and small group, as well as individual assignments. Successful grouping strategies may become an effective way to solve certain problems: working in mixed groups of different competency levels will, for example, improve weaker students’ skills and abilities as they learn from stronger ones working together with them for achieving a common goal. Working in groups of same competency level will, in its turn, give weaker students an opportunity to fully show one’s potential, while encouraging for achieving better results observing the work of a stronger group. However, no matter what methods a teacher chooses, one should be sure to prepare a variety of learning materials of various levels so that the learning needs of all the students in the classroom are met (DelliCarpini). As a result, performing tasks corresponding to their proficiency level, will, with time, bring weaker students closer to the level of more proficient ones. At the same time it should be remembered that work on all of the skills necessary for effective communication in English (reading, writing, listening and speaking) should be integrated. That is they all should be worked on in complex. Such an approach will provide students with the understanding of the importance of all of them. Besides, the more communication takes place in the classroom, whether individually or in groups, the better and faster all the students will be learning the material. Therefore, small team or large group discussions, whether in same level or mixed groups, is to help all the students improve and develop their language skills. Reference:DelliCarpini, Margo. Scaffolding and Differentiating Instruction in Mixed Ability ESL Classes Using a Round Robin Activity. The Internet TESL Journal. Vol. XII, No. 3 (March 2006). 1 February 2009 .