The federation's disciplinary council said it had upheld the charge against the 41-year-old forward in full and imposed a fine of €255 (£215).
Ronaldo left Portugal's base in Copenhagen before their Nations League match against Denmark earlier this month, having accused Jesus of twice breaking his word about his role after he was an unused substitute against Norway.
Jesus denied making any agreement with Ronaldo but left the door open for his return following Portugal's 2-1 win.
The disciplinary council's non-professional section found Ronaldo had intentionally committed an offence under Article 160(1) of the federation's disciplinary regulations.
Proceedings were opened on October 9 over facts reported two days earlier.
The statement did not specify which matches or activities the suspension would cover, or whether time already served under a provisional suspension would count towards the 30-day sanction.
Ronaldo later apologised for failing to acknowledge supporters after the Norway match and for leaving his teammates, saying he remained available for selection after serving any punishment arising from the incident.
Portuguese FA president Pedro Proenca has said everyone within the federation wanted Ronaldo to return to the national team once the matter was resolved.
"On these grounds and for the reasons set out above, the Disciplinary Council – Non-Professional Section – of the Portuguese Football Federation decides, in these proceedings, to uphold the charges in full and, consequently, convict the Defendant Cristiano Ronaldo dos Santos Aveiro of committing, once and intentionally, the disciplinary offence provided for and sanctioned by Article 160(1) of the RDFPF, consequently imposing a 30-day suspension and, additionally, a fine set at 2.5 UC, that is, €255.00 (two hundred and fifty-five euros)", the ruling reads.
In the document released on Monday, the Disciplinary Council also states that "the defendant (Cristiano Ronaldo) also requested that the mitigating circumstances provided for in points c) ('the provision of services of relevance to football'), d) ('a commendation for sporting merit') and e) ('a decisive contribution to the discovery of the material truth') of Article 44(1) of the RDFPF be taken into consideration. To this end, the player cites, on the one hand, his sporting career, honours and distinctions and, on the other, the public statement he issued on 06.10.2026."
The 42-year-old Portuguese forward of Al Nassr faced a suspension of between one and six months, as well as a fine, for leaving the Portugal squad. "A player who, having been regularly called up, leaves or unjustifiably fails to attend training, a match or an activity of the national teams, or one related to the sporting representation of the FPF or Portugal, shall be sanctioned with a suspension of between one and six months and, additionally, if a professional player, with a fine of between 5 and 10 UC", according to the regulations.