diff --git a/src/EFCore/Query/Internal/NullCheckRemovingExpressionVisitor.cs b/src/EFCore/Query/Internal/NullCheckRemovingExpressionVisitor.cs
index 8482d63a307..c6300a97b1e 100644
--- a/src/EFCore/Query/Internal/NullCheckRemovingExpressionVisitor.cs
+++ b/src/EFCore/Query/Internal/NullCheckRemovingExpressionVisitor.cs
@@ -24,7 +24,9 @@ protected override Expression VisitBinary(BinaryExpression binaryExpression)
     {
         var visitedExpression = base.VisitBinary(binaryExpression);
 
-        return TryOptimizeConditionalEquality(visitedExpression) ?? visitedExpression;
+        return TryOptimizeConditionalEquality(visitedExpression)
+            ?? TryOptimizeQueryableNullCheck(visitedExpression)
+            ?? visitedExpression;
     }
 
     /// <summary>
@@ -115,6 +117,34 @@ protected override Expression VisitConditional(ConditionalExpression conditional
         return null;
     }
 
+    private static Expression? TryOptimizeQueryableNullCheck(Expression expression)
+    {
+        // Optimize IQueryable/DbSet null checks:
+        // * IQueryable != null => true
+        // * IQueryable == null => false
+        if (expression is BinaryExpression
+            {
+                NodeType: ExpressionType.Equal or ExpressionType.NotEqual
+            } binaryExpression)
+        {
+            var isLeftNull = IsNullConstant(binaryExpression.Left);
+            var isRightNull = IsNullConstant(binaryExpression.Right);
+
+            if (isLeftNull != isRightNull)
+            {
+                var nonNullExpression = isLeftNull ? binaryExpression.Right : binaryExpression.Left;
+
+                if (nonNullExpression.Type.IsAssignableTo(typeof(IQueryable)))
+                {
+                    var result = binaryExpression.NodeType == ExpressionType.NotEqual;
+                    return Expression.Constant(result);
+                }
+            }
+        }
+
+        return null;
+    }
+
     private sealed class NullSafeAccessVerifyingExpressionVisitor : ExpressionVisitor
     {
         private readonly ISet<Expression> _nullSafeAccesses = new HashSet<Expression>(ExpressionEqualityComparer.Instance);
diff --git a/test/EFCore.Cosmos.FunctionalTests/Query/NorthwindWhereQueryCosmosTest.cs b/test/EFCore.Cosmos.FunctionalTests/Query/NorthwindWhereQueryCosmosTest.cs
index f91ad1dee97..2a93b5d8fba 100644
--- a/test/EFCore.Cosmos.FunctionalTests/Query/NorthwindWhereQueryCosmosTest.cs
+++ b/test/EFCore.Cosmos.FunctionalTests/Query/NorthwindWhereQueryCosmosTest.cs
@@ -1699,6 +1699,22 @@ public override async Task Where_Queryable_AsEnumerable_Contains_negated(bool as
         AssertSql();
     }
 
+    public override async Task Where_Queryable_not_null_check_with_Contains(bool async)
+    {
+        // Cosmos client evaluation. Issue #17246.
+        await AssertTranslationFailed(() => base.Where_Queryable_not_null_check_with_Contains(async));
+
+        AssertSql();
+    }
+
+    public override async Task Where_Queryable_null_check_with_Contains(bool async)
+    {
+        // Cosmos client evaluation. Issue #17246.
+        await AssertTranslationFailed(() => base.Where_Queryable_null_check_with_Contains(async));
+
+        AssertSql();
+    }
+
     public override Task Where_list_object_contains_over_value_type(bool async)
         => Fixture.NoSyncTest(
             async, async a =>
diff --git a/test/EFCore.Specification.Tests/Query/NorthwindWhereQueryTestBase.cs b/test/EFCore.Specification.Tests/Query/NorthwindWhereQueryTestBase.cs
index e4beae2c27e..6abf5422980 100644
--- a/test/EFCore.Specification.Tests/Query/NorthwindWhereQueryTestBase.cs
+++ b/test/EFCore.Specification.Tests/Query/NorthwindWhereQueryTestBase.cs
@@ -1438,6 +1438,27 @@ public virtual Task Where_Queryable_ToArray_Length_member(bool async)
             assertOrder: true,
             elementAsserter: (e, a) => AssertCollection(e, a));
 
+    [ConditionalTheory, MemberData(nameof(IsAsyncData))]
+    public virtual Task Where_Queryable_not_null_check_with_Contains(bool async)
+        => AssertQuery(
+            async,
+            ss =>
+            {
+                var ids = ss.Set<Customer>().Select(c => c.CustomerID);
+                return ss.Set<Customer>().Where(c => ids != null && ids.Contains(c.CustomerID));
+            });
+
+    [ConditionalTheory, MemberData(nameof(IsAsyncData))]
+    public virtual Task Where_Queryable_null_check_with_Contains(bool async)
+        => AssertQuery(
+            async,
+            ss =>
+            {
+                var ids = ss.Set<Customer>().Select(c => c.CustomerID);
+                return ss.Set<Customer>().Where(c => ids == null || !ids.Contains(c.CustomerID));
+            },
+            assertEmpty: true);
+
     [ConditionalTheory, MemberData(nameof(IsAsyncData))]
     public virtual Task Where_collection_navigation_ToList_Count(bool async)
         => AssertQuery(
diff --git a/test/EFCore.SqlServer.FunctionalTests/Query/NorthwindWhereQuerySqlServerTest.cs b/test/EFCore.SqlServer.FunctionalTests/Query/NorthwindWhereQuerySqlServerTest.cs
index 63a234e7e7c..2cc60852b77 100644
--- a/test/EFCore.SqlServer.FunctionalTests/Query/NorthwindWhereQuerySqlServerTest.cs
+++ b/test/EFCore.SqlServer.FunctionalTests/Query/NorthwindWhereQuerySqlServerTest.cs
@@ -1890,6 +1890,36 @@ ORDER BY [c].[CustomerID]
 """);
     }
 
+    public override async Task Where_Queryable_not_null_check_with_Contains(bool async)
+    {
+        await base.Where_Queryable_not_null_check_with_Contains(async);
+
+        AssertSql(
+            """
+SELECT [c].[CustomerID], [c].[Address], [c].[City], [c].[CompanyName], [c].[ContactName], [c].[ContactTitle], [c].[Country], [c].[Fax], [c].[Phone], [c].[PostalCode], [c].[Region]
+FROM [Customers] AS [c]
+WHERE [c].[CustomerID] IN (
+    SELECT [c0].[CustomerID]
+    FROM [Customers] AS [c0]
+)
+""");
+    }
+
+    public override async Task Where_Queryable_null_check_with_Contains(bool async)
+    {
+        await base.Where_Queryable_null_check_with_Contains(async);
+
+        AssertSql(
+            """
+SELECT [c].[CustomerID], [c].[Address], [c].[City], [c].[CompanyName], [c].[ContactName], [c].[ContactTitle], [c].[Country], [c].[Fax], [c].[Phone], [c].[PostalCode], [c].[Region]
+FROM [Customers] AS [c]
+WHERE [c].[CustomerID] NOT IN (
+    SELECT [c0].[CustomerID]
+    FROM [Customers] AS [c0]
+)
+""");
+    }
+
     public override async Task Where_collection_navigation_ToList_Count(bool async)
     {
         await base.Where_collection_navigation_ToList_Count(async);