After the Catalan government failed to pass the regional budget in Parliament on 13 March 2024, as a result of differences with ECP over the Hard Rock mega resort, Aragonès announced a snap election for 12 May.

Illa was elected as new president on 8 August 2024 with the support of ERC and Comuns Sumar and amidst a failed attempt by Puigdemont to thwart his investiture by returning to Barcelona while evading Spanish and Catalan police forces.

[b] Voting for the Parliament was on the basis of universal suffrage, which comprised all nationals over 18 years of age, registered in Catalonia and in full enjoyment of their political rights.

[5] The expat vote system was attributed responsibility for a major decrease in the turnout of Spaniards abroad during the years it had been in force.

[6] The 135 members of the Parliament of Catalonia were elected using the D'Hondt method and a closed list proportional representation, with an electoral threshold of three percent of valid votes—which included blank ballots—being applied in each constituency.

[4] The president had the prerogative to dissolve the Parliament of Catalonia and call a snap election, provided that no motion of no confidence was in process and that dissolution did not occur before one year had elapsed since a previous one under this procedure.

[4] After the Catalan government failed to pass the regional budget on 13 March 2024, president Pere Aragonès announced a snap election for 12 May.

[30] On 21 March, Together for Catalonia (Junts) leader Carles Puigdemont, who fled to Belgium to avoid charges brought by Spanish authorities following the unrecognized referendum on Catalan independence from Spain in 2017, held a rally in Elne, France, near the Spanish border, saying that he would stand for office in the Parliament of Catalonia and seek to become regional president, which he had previously held prior to his exile.

[35] On 26 March, Puigdemont announced the "Vernet Accord", an electoral alliance between Junts and several minor pro-independence parties: his former allies of Action for the Republic (AxR), The Greens–Green Alternative (EV–AV), Independence Rally (RI.cat), Democrats of Catalonia (DC) and Left Movement of Catalonia (MESCat), and new ones such as Catalan State (EC) and Republican Youth of Lleida (JRL).

[39] On 25 March, Catalan Alliance, a far-right party that led the local governments in the municipalities of Ripoll and Ribera d'Ondara, announced that they would be contesting the election with their leader, Sílvia Orriols, as their main candidate.

[43] On 8 May, PSC, ERC, Junts, Comuns Sumar and CUP announced an Acord antifeixista (English: "Anti-fascist Accord"), an agreement that those parties would not enter into any coalition with Catalan Alliance or Vox.

The table below lists opinion polling on the perceived likelihood of victory for each party in the event of a regional election taking place.

[74] On 29 July, ERC announced that it had reached an agreement to elect Illa as new regional president in exchange for executive powers to the Catalan government for collecting, managing and inspecting taxes.