Transformers have rapidly gained popularity in computer vision, especially in the field of object detection.Upon examining the outcomes of state-of-the-art object detection methods, we noticed that transformersconsistently outperformed well-established CNN-based detectors in almost every video or image dataset. Smallobjects have been identified as one of the most challenging object types in detection frameworks due to theirlow visibility. This article aims to explore the performance benefits offered by such extensive networks andidentify potential reasons for their Small Object Detection (SOD) superiority. We aim to investigate potentialstrategies that could further enhance transformers’ performance in SOD. This survey presents a taxonomy ofover 60 research studies on developed transformers for the task of SOD, spanning the years 2020 to 2023. Thesestudies encompass a variety of detection applications, including SOD in generic images, aerial images, medicalimages, active millimeter images, underwater images, and videos. We also compile and present a list of 12large-scale datasets suitable for SOD that were overlooked in previous studies and compare the performanceof the reviewed studies using popular metrics such as mean Average Precision (mAP), Frames Per Second(FPS), and number of parameters. Researchers can keep track of newer studies on our web page, which isavailable at: https://github.com/arekavandi/Transformer-SOD.