diff --git a/esphome/core/config.py b/esphome/core/config.py
index d4a839cb79..e112720f2b 100644
--- a/esphome/core/config.py
+++ b/esphome/core/config.py
@@ -589,7 +589,10 @@ async def _add_looping_components() -> None:
 async def to_code(config: ConfigType) -> None:
     cg.add_global(cg.global_ns.namespace("esphome").using)
     # These can be used by user lambdas, put them to default scope
+    # picolibc (IDF 6.0+) declares isnan in global scope, conflicting with using std::isnan
+    cg.add_global(cg.RawStatement("#ifndef __PICOLIBC__"))
     cg.add_global(cg.RawExpression("using std::isnan"))
+    cg.add_global(cg.RawStatement("#endif"))
     cg.add_global(cg.RawExpression("using std::min"))
     cg.add_global(cg.RawExpression("using std::max"))