The reign of Skandagupta marked the beginning of the decline of the Gupta Empire. In spite of the sweeping military success against the Pushyamitras and the Huns, the strain of constant war depleted the resources of the realm. The debased coinage and the lack of variety of coins during Skandagupta testified the financial drain of the royal exchequer of the Guptas. The death of Skandagupta and the short reign of Puru Gupta hastened the pace of decline. The latter rulers could not hold back the administration of the vast Gupta Empire. Buddha Gupta was the last great ruler who tried to halt the process of decline for sometime, but his hold over the western part of the Gupta Empire was very weak. The feudatories of Kathiawar and Bundelkhand region had assumed a semi-independent status during his reign. The Maitrakas of Valabhi became the hereditary rulers and unfurled the flag of their independence. The other provincial governors of Bundelkhand, Uchchakalpa etc. also declared their independence, defying the dominion of Buddha Gupta. In Jaipur, in Uttar Pradesh and in Narmada valley, the local governors became the de-facto sovereign. Brahmadatta, the governor of Pundravardhana in North Bengal had assumed the high-sounding title of 'Uparika Maharaja' and thus declared his independence. All these factors led to the decline of the Gupta authority in the outlying provinces during the reign of Buddhagupta. The Vakataka invasion in Malwa reduced the authority of Buddhagupta in that region also. As a result, forces of disintegration set within the Gupta Empire and it augmented after the death of Buddhagupta.
The discord within the imperial family was supposed to be the primary cause for the decline of the Gupta Empire. After the death of Kumaragupta I there was probably a struggle for succession among the successors. However Skandagupta did ascend the throne. But the family feud initiated by the successors of Kumaragupta continued even in the following generations, which weakened the family integrity of the Gupta Dynasty. Since the latter Guptas were busy in civil war over the accession to the throne, they could not pay attention towards the administrative maintenance of the vast Empire. Thus the struggle for throne inside the family substantially weakened the central authority in the provinces and feudatories. Thus family grudges continued to be the primary reason for the downfall of the Guptas.
The Vakatakas in Deccan were powerful neighbours of the Guptas. Since Samudragupta projected his campaign in eastern Deccan, the Vakatakas in western Deccan were left unscathed. Chandragupta II had established matrimonial relations with them, by accepting Rudrasena II, the Vakataka king, as the husband of his daughter, Prabhabati Gupta. But the successors of Chandragupta II did not maintain peaceful relations with the Vakatakas. During the reign of Buddha Gupta, the Vakataka king Narendrasena had invaded Malwa, Kosala and Mekala. His invasion considerably had weakened the Gupta authority over the regions of central India and Bundelkhand. Later the Vakatakas ousted the Gupta supremacy from the regions of Malwa and Gujarat.
Since the later Guptas could not check the forces of disintegration, hence, there absence of strong centralised administration. Thus, lack of a centralised management contributed to a steady downfall of the Guptas. Provincial administration was extremely weak and consequently the regional governors enjoyed a great deal of authority and freedom. Again due to exhaustion of the royal exchequer, the Guptas were suffering from shortage of money and accordingly could not spend enough money for provincial administration. Finally the local chiefs or the governors, who were working under the supremacy of the central authority, unfurled the flag of independence. Thus the vast Gupta Empire was disintegrated into provinces and was ruled by local governors, who were originally feudatories of the Gupta suzerain.
The final and perhaps the most important cause for the downfall of the Guptas were the repeated Hun invasions. Though Dr. R.C. Majumdar is of the opinion that Skandagupta successfully had delayed the violent Hun invasion by Toraman and Narasimha Gupta had suppressed the forthcoming invasions, yet most of the historians are inclined to suggest that the Hun incursion had brought about the immediate downfall of the Guptas. Internal dissension already had decomposed the base of the Gupta family and the Hun invasion was just adding of fuel to fire. The Hun plunderings not only exhausted the royal exchequer but also weakened the military organisation of the Guptas. The Hun inroads in western India completely had destroyed the lucrative trade of the Guptas with Rome. The ports and markets of western India were completely devastated due to the invasion of the Huns and their associates.
Finally after the death of Buddha Gupta, the vast and integrated Gupta Empire was crumbled and the local chiefs rose to power. Narasimha Gupta just had no strong influence over the Gupta Empire. As is suggested by historians, the later Guptas were ruling in diminished glory over Magadha, north Bengal and parts of Kalinga. In this process the Gupta supremacy was diminished and the Maukharis finally ousted them from Magadha and Ishanavarmana Maukhari ascended the throne assuming the title of 'Maharajadhiraja' in 554 A.D.