The Orthomyxoviridae family includes influenza D virus (IDV), an emerging pathogen primarily affecting cattle and swine; there is evidence of cross-species transmission and potential zoonotic risk. Although active human infections have yet to be confirmed, high seroprevalence in cattle-exposed populations highlights the need for continued surveillance. We developed and validated a rapid, field-deployable reverse transcription loop-mediated isothermal amplification assay for IDV detection; specificity was 99.2% and sensitivity ranged from 95.6% (cycle quantification <30) to 81.8% (cycle quantification <40). This method offers a cost-effective, accessible alternative to quantitative reverse transcription PCR, enabling improved monitoring of IDV and reinforcing preparedness for emerging influenza threats.