ARMSCII or ArmSCII is a set of obsolete single-byte character encodings for the Armenian alphabet defined by Armenian national standard 166-9. ArmSCII is an acronym for Armenian Standard Code for Information Interchange, similar to ASCII for the American standard. It has been superseded by the Unicode standard.

However these encodings are not widely used because the standard was published one year after the publication of international standard ISO 10585 that defined another 7-bit encoding, from which the encoding and mapping to the UCS (Universal Coded Character Set (ISO/IEC 10646) and Unicode standards) were also derived a few years after, and there was a lack of support in the computer industry for adding ArmSCII.

Very few systems support these encodings. Windows does not support them, for example. It is usually better to use Unicode for proper interchange of Armenian text for web browsers and email, since most modern computers do not support ArmSCII by default.

The following three main variants are defined: