diff --git a/datafusion/sql/src/select.rs b/datafusion/sql/src/select.rs
index d5a55e0325f8..33994b60b735 100644
--- a/datafusion/sql/src/select.rs
+++ b/datafusion/sql/src/select.rs
@@ -29,7 +29,7 @@ use crate::utils::{
 
 use datafusion_common::error::DataFusionErrorBuilder;
 use datafusion_common::tree_node::{TreeNode, TreeNodeRecursion};
-use datafusion_common::{not_impl_err, plan_err, DataFusionError, Result};
+use datafusion_common::{not_impl_err, plan_err, Result};
 use datafusion_common::{RecursionUnnestOption, UnnestOptions};
 use datafusion_expr::expr::{Alias, PlannedReplaceSelectItem, WildcardOptions};
 use datafusion_expr::expr_rewriter::{
@@ -85,7 +85,7 @@ impl<S: ContextProvider> SqlToRel<'_, S> {
 
         // Handle named windows before processing the projection expression
         check_conflicting_windows(&select.named_window)?;
-        match_window_definitions(&mut select.projection, &select.named_window)?;
+        self.match_window_definitions(&mut select.projection, &select.named_window)?;
         // Process the SELECT expressions
         let select_exprs = self.prepare_select_exprs(
             &base_plan,
@@ -868,42 +868,34 @@ impl<S: ContextProvider> SqlToRel<'_, S> {
 
         Ok((plan, select_exprs_post_aggr, having_expr_post_aggr))
     }
-}
-
-// If there are any multiple-defined windows, we raise an error.
-fn check_conflicting_windows(window_defs: &[NamedWindowDefinition]) -> Result<()> {
-    for (i, window_def_i) in window_defs.iter().enumerate() {
-        for window_def_j in window_defs.iter().skip(i + 1) {
-            if window_def_i.0 == window_def_j.0 {
-                return plan_err!(
-                    "The window {} is defined multiple times!",
-                    window_def_i.0
-                );
-            }
-        }
-    }
-    Ok(())
-}
 
-// If the projection is done over a named window, that window
-// name must be defined. Otherwise, it gives an error.
-fn match_window_definitions(
-    projection: &mut [SelectItem],
-    named_windows: &[NamedWindowDefinition],
-) -> Result<()> {
-    for proj in projection.iter_mut() {
-        if let SelectItem::ExprWithAlias { expr, alias: _ }
-        | SelectItem::UnnamedExpr(expr) = proj
-        {
-            let mut err = None;
-            visit_expressions_mut(expr, |expr| {
-                if let SQLExpr::Function(f) = expr {
-                    if let Some(WindowType::NamedWindow(_)) = &f.over {
-                        for NamedWindowDefinition(window_ident, window_expr) in
-                            named_windows
-                        {
-                            if let Some(WindowType::NamedWindow(ident)) = &f.over {
-                                if ident.eq(window_ident) {
+    // If the projection is done over a named window, that window
+    // name must be defined. Otherwise, it gives an error.
+    fn match_window_definitions(
+        &self,
+        projection: &mut [SelectItem],
+        named_windows: &[NamedWindowDefinition],
+    ) -> Result<()> {
+        let named_windows: Vec<(&NamedWindowDefinition, String)> = named_windows
+            .iter()
+            .map(|w| (w, self.ident_normalizer.normalize(w.0.clone())))
+            .collect();
+        for proj in projection.iter_mut() {
+            if let SelectItem::ExprWithAlias { expr, alias: _ }
+            | SelectItem::UnnamedExpr(expr) = proj
+            {
+                let mut err = None;
+                visit_expressions_mut(expr, |expr| {
+                    if let SQLExpr::Function(f) = expr {
+                        if let Some(WindowType::NamedWindow(ident)) = &f.over {
+                            let normalized_ident =
+                                self.ident_normalizer.normalize(ident.clone());
+                            for (
+                                NamedWindowDefinition(_, window_expr),
+                                normalized_window_ident,
+                            ) in named_windows.iter()
+                            {
+                                if normalized_ident.eq(normalized_window_ident) {
                                     f.over = Some(match window_expr {
                                         NamedWindowExpr::NamedWindow(ident) => {
                                             WindowType::NamedWindow(ident.clone())
@@ -914,20 +906,34 @@ fn match_window_definitions(
                                     })
                                 }
                             }
-                        }
-                        // All named windows must be defined with a WindowSpec.
-                        if let Some(WindowType::NamedWindow(ident)) = &f.over {
-                            err = Some(DataFusionError::Plan(format!(
-                                "The window {ident} is not defined!"
-                            )));
-                            return ControlFlow::Break(());
+                            // All named windows must be defined with a WindowSpec.
+                            if let Some(WindowType::NamedWindow(ident)) = &f.over {
+                                err =
+                                    Some(plan_err!("The window {ident} is not defined!"));
+                                return ControlFlow::Break(());
+                            }
                         }
                     }
+                    ControlFlow::Continue(())
+                });
+                if let Some(err) = err {
+                    return err;
                 }
-                ControlFlow::Continue(())
-            });
-            if let Some(err) = err {
-                return Err(err);
+            }
+        }
+        Ok(())
+    }
+}
+
+// If there are any multiple-defined windows, we raise an error.
+fn check_conflicting_windows(window_defs: &[NamedWindowDefinition]) -> Result<()> {
+    for (i, window_def_i) in window_defs.iter().enumerate() {
+        for window_def_j in window_defs.iter().skip(i + 1) {
+            if window_def_i.0 == window_def_j.0 {
+                return plan_err!(
+                    "The window {} is defined multiple times!",
+                    window_def_i.0
+                );
             }
         }
     }
diff --git a/datafusion/sqllogictest/test_files/window.slt b/datafusion/sqllogictest/test_files/window.slt
index c5c094cad3da..1e64bf3f91ce 100644
--- a/datafusion/sqllogictest/test_files/window.slt
+++ b/datafusion/sqllogictest/test_files/window.slt
@@ -5610,3 +5610,35 @@ DROP TABLE aggregate_test_100_utf8view;
 
 statement ok
 DROP TABLE aggregate_test_100
+
+# window definitions with aliases
+query II rowsort
+SELECT
+  t1.v1,
+  SUM(t1.v1) OVER W + 1
+FROM
+  generate_series(1, 5) AS t1(v1)
+WINDOW
+  w AS (ORDER BY t1.v1);
+----
+1 2
+2 4
+3 7
+4 11
+5 16
+
+# window definitions with aliases
+query II rowsort
+SELECT
+  t1.v1,
+  SUM(t1.v1) OVER w + 1
+FROM
+  generate_series(1, 5) AS t1(v1)
+WINDOW
+  W AS (ORDER BY t1.v1);
+----
+1 2
+2 4
+3 7
+4 11
+5 16