In the Rwandan multilingual context, an overwhelmingly dominant language of everyday communication (viz.: Kinyarwanda) is vying for space on the national linguistic market with three co-official languages. Of these, two (viz.: English and French) are influential internationally and one (viz.: Kiswahili) is influential regionally. This is a rather unique context of language use; and the present study set out to examine how “Translanguaging” as a teaching/learning strategy is likely to foster subject content learning and language competence development at the secondary school level. In this endeavor, the study specifically aimed (1) to describe the nature of Translanguaging as actually practiced in this particular context; (2) to ascertain the way in which it enhances subject content learning; and (3) to determine how it is likely to improve students’ language competence. The following findings were thus reached. With regard to the nature of Translanguaging; the study found that the aspects of the practice referred to as “Integrated Use of Languages” and “Centre Stage to Home Language” were extensively and usefully harnessed, especially through English-Kinyarwanda/KinyarwandaEnglish codeswitching. At the same time, however, the study found that a most important aspect of Translanguaging, the “Integrated Language Use Planning and Activity Structuring” was not observed, and this represents an crucial defect in the practice. As concerns the way in which Translanguaging facilitates Subject Content Learning, the study found that knowledge is effectively delivered and accessed, even though appropriate expression of that knowledge in the academic context is likely to be a big challenge. Finally with respect to how Translanguaging enhances Language Competence Development, the study found that; of all the “linguistic varieties (Franceschini 2011)” most likely to be used in the context under study; only one (viz.: Kinyarwanda-English codeswitching) is sure to develop rapidly, whereas the other varieties (English, French, Kiswahili, and Kinyarwanda) are likely to be learnt and/or developed moderately, owing mainly to the above mentioned “Integrated Language Use Planning” defect. Overall, it has appeared from the present study that; to a certain extent; it is good for secondary school education that teachers and students have intuitively adopted “multilingual practices” as a teaching/learning strategy. However, it would be highly recommended that the practice be consciously planned and systematically monitored and evaluated. Only in that way, it is suggested, multilingual practices can be fully and beneficially harnessed for concomitant advancement of subject content learning and language competence development / MT 2019