The official opening date of the Baku Metro is considered to be November 6, 1967, when it was accepted by the State Commission. However, the metro opened its doors to passengers only on November 25 of the same year. The opening of the metro was timed to coincide with the 50th anniversary of the October Revolution.

Baku became the fifth city in the Soviet Union to build a metro system, after Moscow, Leningrad, Kyiv, and Tbilisi. However, it also became the first city among all Islamic cities in the world—whether socialist or capitalist—to open a metro. For comparison: Tashkent's metro opened only in 1977, Cairo's in 1987, Ankara's in 1996, Tehran's in 1999, Istanbul's in 2000, Kazan's in 2005, and Almaty’s in 2011.

As of the end of 2021, the Baku Metro includes 3 active lines with a total length of 38.3 km and 26 stations. All lines are served by a single depo—Depo No. 1 "Nariman Narimanov." Currently, new stations are under construction on the third line, and a second depo—Depo No. 2 "Darnagul"—is being built.

The fare payment is controlled at the station entrance using turnstiles.
The current fare payment system (via the "BakiKart" transport card) was introduced on March 1, 2006, making the Baku Metro the second in the post-Soviet space, after Moscow, to abandon tokens.

Where can you buy a BakiKart? Special machines are available at all metro stations, allowing you to purchase and top up your BakiKart. The cost of a reusable card is 2 manats. To acquire a reusable card, you need to press the card icon on the machine and insert 2 manats. Once the payment is made, the card is dispensed, after which you can top it up. The cost of one metro ride is 50 coins.

The capital of Azerbaijan is located on the western coast of the Caspian Sea and, along with its suburbs, occupies almost the entire Absheron Peninsula. The central part of the city stretches in a semi-circle along Baku Bay for 24 km, from the Zykh Spit in the east to Shakhovaya in the west.

Baku’s metro stations are divided into 4 types: 7 out of 8 deep-laid stations are pylon-type, one is a single-span station; 14 out of 17 shallow-laid stations are columned three-span stations (with construction designs varying); and the remaining three stations are single-arch. Baku also has one open surface station, "Bakmill," which is unique among the metro systems of the former USSR.

The Baku Metro differs from other metro systems in the CIS countries in that it does not operate on closed loops for specific lines. Instead, there are four train routes on the "main" line, and each station has signs indicating the direction of the next train.

Since the Baku Metro operates along routes, the division into lines is conditional. "Shuttle" trains run only on two sections: "Jafar Jabbarly" — "Shah Ismail Khatai" and "8 November" — "Bus Station." On the so-called "main" line, trains run along the following routes: "Darnagul" — "Azi Aslanov," "Darnagul" — "Bakmill," "Icherisheher" — "Azi Aslanov," "Icherisheher" — "Bakmill." Despite this, the conditional division into lines remains. Currently, the Red Line ("Icherisheher" — "Azi Aslanov") is 18.8 km long and has 13 stations, while the Green Line ("Khatai" — "Darnagul") is 15.54 km long and has 10 stations. In the near future, there are plans to merge the sections "Darnagul" — "Nizami" and "Jafar Jabbarly" — "Shah Ismail Khatai" into a full line, but at the moment, direct movement between them is not possible, even though they are legally considered one line.

On April 19, 2016, the third line, the Purple Line, was opened, initially including two stations: "Bus Station" and "Memar Ajami-2," with a distance of 2.07 km between them. On May 29, 2021, the third station, "8 November," was added, and the line's length increased by 1.6 km. The metro now has two transfer stations. The trains in the Baku Metro consist of five cars, as the stations on the first two lines were designed for this number of cars. For the Purple Line, which can accommodate trains with up to seven cars, five-car trains are still used due to the lower passenger flow. The Baku Metro accounts for about 30% of all urban transportation in the city.