While many Slavic languages officially use Latin-derived names for the months of the year in the Gregorian calendar, there is also a set of older names for the twelve months that differs from the Latin month names, as they are of Slavic origin. In some languages, such as the Serbian language these traditional names have since been archaized and are thus seldom used.

The original names of the months of the year in the Slavic languages closely follow natural occurrences such as weather patterns and conditions common for that period, as well as agricultural activities.

Many months have several alternative names in different regions; conversely, a single "Slavic name" may correspond to different "Roman names" (for different months, usually following each other) in different languages.

The Slavic names of the months have been preserved by a number of Slavic people in a variety of languages. The conventional month names in some of these languages are mixed, including names which show the influence of the Germanic calendar (particularly Slovene, Sorbian, and Polabian)^[1] or names which are borrowed from the Gregorian calendar (particularly Polish and Kashubian), but they have been included here nonetheless.

In the Latvian and Lithuanian languages, the Baltic names of the months are preserved, which partially coincide with the Slavic ones, which suggests that some of these names may date back to the time of the Balto-Slavic linguistic unity. Latvian and Lithuanian names are also shown in this table for comparison.

* word of non-Slavic or non-Baltic origin

The Croatian months used with the Gregorian calendar by Croats differ from the original Latin month names.

The names of Czech months are, as in Belarusian, Croatian, Kashubian, Polish, and Ukrainian, not based on the Latin names used in most European languages. The suffix -en is added to most of the months' names.

The Macedonian language has two sets of names of the months of the Gregorian calendar. The most commonly used set of names is derived from the Latin month names and these are used by the vast majority of the Macedonian population. However, there is also a set of older names for the twelve months of Slavic origin that differ from the Latin month names, although their usage is archaized and largely restricted to folk literature and religious calendars issued by the Macedonian Orthodox Church.

The origin of the Macedonian month names is closely related to the agricultural activities that occur in the corresponding period, or to the weather conditions common for that period. Some months have alternative names in different regions. The usage of modern Latin month names among Macedonians started towards the end of the 19th century, as a result of mass education.

The names of Polish months are, as in Belarusian, Croatian, Czech, Kashubian, and Ukrainian, not based on the Latin names used in most European languages, with the exception of March and May, which were borrowed from the Gregorian calendar.

The names of Russian months used with the Gregorian calendar by vast majority of the Russian population. The most of names for the twelve months of Slavic origin that is differ from the Latin month names and standardized set of archaic that issued by Old Church Slavonic.

Many of the names in the standardized set of archaic Slovene month names first occur in the Škofja Loka manuscript, written in 1466 by Martin of Loka.^[42]

The names of Ukrainian months are not based on the Latin names used in most European languages. Latin names are not used at all, though it's possible to hear distorted versions of Russian or Polish names in surzhyk sometimes. The suffix -en is added to most of the months' names.

• Lithuanian calendar
• Slavic Native Faith's calendars and holidays
• Germanic calendar
• Julian calendar
• Romanian calendar
• Slovene months