There are numerous archaeological sites in the town and its surroundings. They are a symbol of this town's rich history. Excavations in 1997 confirmed that there were people living in the town's wider area as early as 5,500 BC in the Neolithic period. This area continued to be populated through the long and turbulent history and still continues today.

Đakovo is for the first time mentioned in written documents in 1239, in the deed of donation form the Croatian duke Koloman to the Bosnian bishop Ponsi, by which bishops become the masters of Đakovo and the Đakovo area. That is the beginning of the history of the Đakovo Bishopric. Nowadays, Đakovo is still a bishop's town - headquarters of the Đakovačko-srijemska Bishopric. In different periods in its history, the town itself is mentioned under similar names: DYACO, DIACO, DYACOW...

In 1536 the Turks occupied Đakovo and ruled it for almost 150 years - the town then got the name JAKOVA. That was a dark period in the town's history. Almost all Catholic churches were torn down and mosques were built. The best-known is the Ibrahim-pašina Mosque which was turned into a Catholic church after the Turks left. In 1690 the bishop returned to the town and the construction of town begun.

When the Turks left, the construction of a new, more modest cathedral and a bishop's palace started in Đakovo. This was the second of three cathedrals which have so far been built in Đakovo. Its construction was ordered by bishops Patačić and Bakić.

Today's St. Peter's Cathedral-Basilica is built in a combination of the neo-Gothic and the Romanesque style. Bishop Strossmayer started its construction in 1866, when he was 52-years-old and in his 16th year of bishop's service. Construction lasted for full 16 years (until 1882), of which the external construction works lasted for 4 years and the internal decoration of the Cathedral for 12 years. 7,000,000 brick-bats, baked in Đakovo, were used for the construction of the Cathedral. The stone was delivered from Istra, Hungary, Austria, Italy and France. The Cathedral's planning engineers were architects from Vienna, Karlo Rősner and Frederic Schmidt. The internal decoration was entrusted to German painters who lived in Rome, father and son Alexander-Maximilian and Ludwig Seitz. The Cathedral has 7 altars, and is decorated by 43 fresco paintings, 31 sculptures and 32 works of relief, as well as organs with 73 registers, three couplers and 5,486 reeds.

The Đakovo Bishopric and its bishops left numerous evidence of their activity in the town. In 1706 bishop Patačić ordered the renewal of the Horse Farm.

In 1773 Đakovo becomes the centre of the united Bosansko-đakovačka and Srijemska Bishopric, which includes all north-eastern parts of Croatia.

Bishop Antun Mandić opened today's oldest academic institution in Slavonija and Baranja, the Theological seminary. He also undertook large economic interventions on the landed estate, especially in the cultivation of vineyards. His name is preserved in far-famed 'mandićevački' vineyards.

When Josip Juraj Strossmayer was appointed bishop in 1849, the town's development was on a new rise. The Bishop's landed estate became the model of an exemplary economy, and with its considerable income enabled the great bishop to undertake patronage acts till then unseen in Croatia (Croatian Academy of Arts and Sciences, HAZU), and give a new outlook to the new Cathedral in Đakovo and also to numerous church and economic edifices.

Although the year 1506 is considered to be the year of its foundation, the history of the Horse Farm in Đakovo started with the foundation of the Bishopric and the deed of donation of ten Arab horses and one stallion. According to the bishop Bakić, horse breeding on the landed estate has existed since 1374. Breeding continues even today at the State Horse Farm of Lippizaner, which is one of the oldest in Europe, and there is also a large number of private horse breeders. For many years, the Horse Farm was a part of the agro-industrial plant PIK-Đakovo, and today it is the State Horse Farm of Lippizaner, in charge of raising and selection.

Đakovo has always been a town of artisans. In 1813 the association of craftsmen GUILD was founded. The industrial development started with the construction of mills and brickyards, and numerous craftsmen, of various lines of work, with their offer of products contributed to Đakovo becoming, particularly in connection to fairs, a well-known trading centre in whole of Slavonija. Today, Đakovo is a town with over 30,000 inhabitants.