San Francisco is a neo-grotesque sans-serif typeface made by Apple Inc. It was first released to developers on November 18, 2014.

The San Francisco typeface has three variants: "SF" for macOS, iOS, and tvOS; "SF Compact" for watchOS; and "SF Mono" for Xcode 8 and up. The main difference is that the sides of letters with round shapes, such as o, e, and s, are round in SF, whereas they are flat in SF Compact. The flat sides allow the letters to have more space between them, thereby making the text more legible at small sizes, which is particularly important for the Apple Watch.

Both SF and SF Compact each have two optical sizes: "display" for large and "text" for small text. Compared to display, the letters in text have larger apertures and more generous letter-spacing. The operating system automatically chooses the display optical size for sizes of at least 20 points, and the text optical size otherwise.[8] Additionally, included in macOS Sierra and iOS 10 is a new variant named "SF Compact Rounded". It is used in the new contact placeholder icons introduced in the OSs.

San Francisco fonts are dynamic. One of the great features of San Francisco is the way it optimizes the typeface dynamically. The system will automatically switch the Display/Text fonts according to the text size.