Yes, you can open .pptx files in Keynote. Keynote, Apple's presentation software for macOS and iOS, includes built-in support for opening Microsoft PowerPoint's .pptx format. When you open a .pptx file, Keynote automatically attempts to import the presentation and convert it into its own native format. While this conversion works for fundamental elements like text, images, and basic shapes, some complex formatting, transitions, animations, or effects designed specifically for PowerPoint might not translate perfectly or could be simplified.

Common examples include opening PowerPoint presentations created on a Windows PC to edit or present on a Mac using Keynote. Similarly, if someone emails you a .pptx file on your iPhone or iPad, you can open it directly in the Keynote app for viewing or editing. This is frequently used by users collaborating across platforms, educators sharing materials, or professionals in various industries receiving presentations initially built in PowerPoint.

The main advantage is straightforward compatibility between different ecosystems. However, significant limitations exist: complex elements often break or don't display correctly, potentially requiring manual adjustments after opening. Animations, transitions, sophisticated layouts, and specialized fonts are common points of failure. Always carefully review the presentation in Keynote after conversion. For critical work demanding precise visual fidelity, using PowerPoint ensures compatibility. For collaborative workflows across tools, simple presentations fare best, while complex ones carry inherent risks in this conversion process.