After the 2015–2019 Senate term led by President of the Senate Bukola Saraki (Peoples Democratic Party) and with a slight All Progressives Congress majority, the 2019 elections were categorized by a large shift back towards the APC and the defeats of multiple high-profile senators—including Saraki.

As in the House of Representatives, the APC solidified its majority after nearly losing it due to defections in 2018.

At the opening of the 9th Nigeria National Assembly, Ahmad Lawan (APC-Yobe North) was elected as Senate President and Ovie Omo-Agege (APC-Delta Central) became Deputy Senate President as the party avoided the internal struggles that led Saraki and Ike Ekweremadu to take those offices in 2015.

[note 4] More defections occurred in the wake of party primaries as senators decamped to new parties (mainly in order to run for re-election),[note 5] most notably Abaribe who resigned as Minority Leader and joined APGA to run for re-election after withdrawing from the Abia PDP gubernatorial primary.

From the perspective of the APC, analysts viewed the 9th Senate as a change from the legislature versus executive disputes that were commonplace during the 8th Senate but critics derided the chamber as a rubber stamp that lacked the initiative to advocate for itself against the executive branch.