This thesis reports the findings of three studies designed to investigate the influences of backgrounds on learners and instructors in learning and teaching second language (L2) writing in English. The participants, thus, were learners and instructors of L2 writing in English. The studies took place in the ESL context of New Zealand and in the EFL context of Bangladesh. The first two studies focused on how learners from various linguistic, academic, and cultural backgrounds learned to write in English. The third study demonstrated how instructors’ academic training and the context of teaching influenced their modes of teaching L2 writing in English in Bangladesh. In the first study, 30 participants were recruited from an English Language College in New Zealand. All participants were honing their English language skills in order to embark on undergraduate or graduate studies in New Zealand. Their proficiency in the English language was similar given the results of a placement test. The age of participants ranged from 16-40 years, and they came from such countries as China, Thailand, Indonesia, Japan, and Colombia. Participants were divided based on Chinese (N=20) and non-Chinese (N=10) backgrounds. All participants completed background questionnaires, grammaticality judgement tests, vocabulary tests, and writing tasks. A critical finding of this study was that for the non-Chinese participants both vocabulary and grammar tests’ scores correlated with the scores of the writing test; however, for the Chinese learners, scores in the vocabulary test did not correlate with those of the writing and grammar tests. This suggested that the L2 writers across cultures and languages did not learn to write in English exactly alike, though participants of this study also demonstrated some similar areas of L2 writing development. The study reinforced the caution about generalizing L2 writers across languages, cultures, and academic backgrounds. The second study included 70 undergraduate students from a private university in the capital city of Bangladesh, Dhaka. The age of the participants ranged from 17-24 years, and their native language was Bangla. English language development was similar across participants given the results of an admission test and the mandatory pre-requisite English courses taken. Participants completed background questionnaires, vocabulary tests, grammaticality judgement tests, and writing tasks in English and Bangla. Participants also completed a questionnaire that gleaned information about their perceptions of writing in English and Bangla. One of the critical findings of the study was the cross-language correlations between essays, implying that a strong or a weak writer in a first language would show similar ability levels in an L2. This study suggested that the teaching of L2 writing in English should be based on an appreciation of how the development of writing in an L1 can help or hinder the development of writing in an L2. The third study focused on L2 writing instructors at different public and private universities in Bangladesh. This study included 46 participants who completed background questionnaires, provided feedback on a piece of writing and completed questionnaires that gleaned information regarding their styles and strategies of providing feedback. The study revealed that the areas of specialization in English studies between the junior and senior instructors significantly varied--senior instructors specialized mostly in literature, whereas the junior instructors mostly specialized in language-related areas. Despite this, their practice and perceptions of teaching L2 writing across the universities in Bangladesh did not vary significantly. This may change over time as instructors with language -area specializations become the majority in the future. The three studies of this thesis shifted the focus from learning to teaching L2 writing across contexts and languages. The findings should inform explanation of why learners from different linguistic and cultural backgrounds, and with differing language abilities, learned or failed to learn to write in English. Furthermore, empirical data were presented to appreciate influences on instruction which in turn would influence the ways learners learn L2 writing in English. Such findings should support the development of theories and practices in the teaching and learning of L2 writing.