Reports confirm that a member of the Qatari security forces was killed in the Israeli airstrike in Doha, indicating that Qatari civilians were among the dead, though the majority of casualties were Hamas members.
Unconfirmed reports are saying that Qatari civilians were amongst the dead

Our Friends (and Hamas’s Friends) the Qataris - National Review
Source: nationalreview.com
Key Evidence
Middle East Eye reports a named Qatari security force member killed in the attack.
middleeasteye.netmiddleeasteye.netMember of Qatari security forces amongst those killed in Israeli attack on Doha
RTE News confirms six dead including a Qatari security officer.
rte.ierte.ieLive: Six dead in Doha including Qatari security officer
Multiple sources confirm five Hamas members killed but do not mention other civilian casualties.
cbc.cacbc.caHamas says 5 of its members killed, including son of top leader, in Israeli...
apnews.comapnews.comHamas says top leaders survived Israeli strike on Qatar while five lower-ranking...
What the Evidence Shows
The input claim states that unconfirmed reports suggest Qatari civilians were among the dead in an Israeli airstrike in Qatar. Multiple sources confirm that at least one Qatari individual, specifically a member of the Qatari security forces, was killed during the attack. For example, Middle East Eye identifies Lance Corporal Badr Saad Mohammed al-Humaidi al-Dosari as a casualty. RTE News also reports six dead including a Qatari security officer. These details substantiate that Qatari nationals were indeed among those killed.middleeasteye.netmiddleeasteye.netMember of Qatari security forces amongst those killed in Israeli attack on Doha
rte.ierte.ieLive: Six dead in Doha including Qatari security officer
However, most sources emphasize that the majority of casualties were Hamas members targeted in the strike. CBC News and AP News report five Hamas members killed, including lower-ranking officials, with Hamas leadership surviving. There is no explicit mention of civilian casualties beyond the security personnel, who may be considered government-affiliated rather than purely civilian.cbc.cacbc.caHamas says 5 of its members killed, including son of top leader, in Israeli...
apnews.comapnews.comHamas says top leaders survived Israeli strike on Qatar while five lower-ranking...
The term "Qatari civilians" is somewhat ambiguous here. The confirmed death of a security force member indicates at least some Qatari nationals died, but whether they were civilians or official personnel is clearer for the latter. No sources explicitly confirm deaths of non-security force civilian Qataris.
In summary:
Confirmed: At least one Qatari security force member was killed.
Confirmed: Several Hamas members were killed.
Unconfirmed: Deaths of other Qatari civilians beyond security personnel.
Therefore, while it is accurate that Qataris died in the attack, the claim that "Qatari civilians" broadly were among the dead remains partially unverified beyond the known security officer casualty.