影像扫描仪，常简称扫描仪，是一个能够把相片、印刷文档或手写文档等影像，或装饰品等小对象扫描、分析并化成数码影像的器材。

现在大部份影像扫描仪都是桌面扫描仪的变种。以手动作扫描的手提扫描仪曾一度流行，但由于很难获得理想影像质素，现已被淘汰。这些扫描仪都使用电荷耦合器（Charge-coupled device，CCD）作为影像感应器，而鼓式扫描仪则采用光电倍增管（Photomultiplier Tube）作为影像感应器。影像扫描仪在我们日常生活中十分重要，随处都有它的存在。

其他种类的扫描仪包括planetary扫描仪，可为书籍及文档拍摄影像，及激光距离扫描仪（Laser Range scanner），可制作立体三维空间对象的模型。

In computing, an image scanner—often abbreviated to just scanner, although the term is ambiguous out of context (barcode scanner, CAT scanner, etc.)—is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Commonly used in offices are variations of the desktop flatbed scanner where the document is placed on a glass window for scanning. Hand-held scanners, where the device is moved by hand, have evolved from text scanning "wands" to 3D scanners used for industrial design, reverse engineering, test and measurement, orthotics, gaming and other applications. Mechanically driven scanners that move the document are typically used for large-format documents, where a flatbed design would be impractical.