Have Shia and Sunni ever been allies ?
Research institutes
CFR's Yemen tracker frames that war as a decades-long regional proxy struggle along the Sunni-Shia divide, with Saudi Arabia backing Yemen's internationally recognized (Sunni-aligned) government against Iran's Shia-aligned Houthi movement. Its Iraq tracker, by contrast, records a Shia-led Baghdad government engaging Syria's Sunni interim leadership and Kurdish partners on shared security concerns even as it works to curb Iran-aligned Shia militias.
News & reporting
Reporting shows a mixed picture: Gulf Arab (Sunni-majority) states have kept diplomatic channels open to Shia-ruled Iran even after their 2026 war, seeking cooperation rather than confrontation, while Saudi Arabia, Turkey and Pakistan have simultaneously built a rival Sunni-aligned coalition against the Shia Houthi movement.
Justice Council Political Analysis
Cross-sectarian alliances between Sunni and Shia actors do occur, but the record shows they are driven by state interest, threat-perception and balance-of-power calculations rather than sectarian solidarity — and they remain less common than sect-aligned coalitions, because the deepest current security relationships in the region (Saudi-Turkey-Pakistan, US-Gulf) have formed against Iran-backed Shia actors, while sect-crossing cooperation (Gulf-Iran talks, Iraq-Syria coordination) tends to be transactional and issue-specific rather than a durable alliance.
Durable Sunni-Shia alliance requires institutionalising ad hoc openings — formal GCC-Iran dialogue mechanisms and concrete militia-disarmament steps in Iraq — so that transactional cooperation converts into a stable arrangement; without that, the proxy dynamics documented in the Yemen record will keep reproducing sect-aligned blocs.
Conclusion
Yes: the corpus shows Sunni and Shia states and factions do ally or cooperate, but only when interest dictates it — the pattern is exceptional and transactional rather than a norm. The dominant, better-documented pattern remains sect-aligned rivalry, with cross-sect cooperation appearing as pragmatic diplomacy or governance necessity rather than sectarian reconciliation.