diff --git a/src/EFCore.SqlServer/Extensions/SqlServerDbFunctionsExtensions.cs b/src/EFCore.SqlServer/Extensions/SqlServerDbFunctionsExtensions.cs
index 6eef2786a8e..30ab9fb03ee 100644
--- a/src/EFCore.SqlServer/Extensions/SqlServerDbFunctionsExtensions.cs
+++ b/src/EFCore.SqlServer/Extensions/SqlServerDbFunctionsExtensions.cs
@@ -976,7 +976,7 @@ public static TimeSpan TimeFromParts(
         public static int? DataLength(
             [CanBeNull] this DbFunctions _,
             [CanBeNull] string arg)
-            => throw new InvalidOperationException(SqlServerStrings.FunctionOnClient(nameof(DataLength)));
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
 
         /// <summary>
         ///     Returns the number of bytes used to represent any expression.
@@ -987,7 +987,7 @@ public static TimeSpan TimeFromParts(
         public static int? DataLength(
             [CanBeNull] this DbFunctions _,
             bool? arg)
-            => throw new InvalidOperationException(SqlServerStrings.FunctionOnClient(nameof(DataLength)));
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
 
         /// <summary>
         ///     Returns the number of bytes used to represent any expression.
@@ -998,7 +998,7 @@ public static TimeSpan TimeFromParts(
         public static int? DataLength(
             [CanBeNull] this DbFunctions _,
             double? arg)
-            => throw new InvalidOperationException(SqlServerStrings.FunctionOnClient(nameof(DataLength)));
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
 
         /// <summary>
         ///     Returns the number of bytes used to represent any expression.
@@ -1009,7 +1009,7 @@ public static TimeSpan TimeFromParts(
         public static int? DataLength(
             [CanBeNull] this DbFunctions _,
             decimal? arg)
-            => throw new InvalidOperationException(SqlServerStrings.FunctionOnClient(nameof(DataLength)));
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
 
         /// <summary>
         ///     Returns the number of bytes used to represent any expression.
@@ -1020,7 +1020,7 @@ public static TimeSpan TimeFromParts(
         public static int? DataLength(
             [CanBeNull] this DbFunctions _,
             DateTime? arg)
-            => throw new InvalidOperationException(SqlServerStrings.FunctionOnClient(nameof(DataLength)));
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
 
         /// <summary>
         ///     Returns the number of bytes used to represent any expression.
@@ -1031,7 +1031,7 @@ public static TimeSpan TimeFromParts(
         public static int? DataLength(
             [CanBeNull] this DbFunctions _,
             TimeSpan? arg)
-            => throw new InvalidOperationException(SqlServerStrings.FunctionOnClient(nameof(DataLength)));
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
 
         /// <summary>
         ///     Returns the number of bytes used to represent any expression.
@@ -1042,7 +1042,7 @@ public static TimeSpan TimeFromParts(
         public static int? DataLength(
             [CanBeNull] this DbFunctions _,
             DateTimeOffset? arg)
-            => throw new InvalidOperationException(SqlServerStrings.FunctionOnClient(nameof(DataLength)));
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
 
         /// <summary>
         ///     Returns the number of bytes used to represent any expression.
@@ -1053,7 +1053,7 @@ public static TimeSpan TimeFromParts(
         public static int? DataLength(
             [CanBeNull] this DbFunctions _,
             [CanBeNull] byte[] arg)
-            => throw new InvalidOperationException(SqlServerStrings.FunctionOnClient(nameof(DataLength)));
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
 
         /// <summary>
         ///     Returns the number of bytes used to represent any expression.
@@ -1064,6 +1064,6 @@ public static TimeSpan TimeFromParts(
         public static int? DataLength(
             [CanBeNull] this DbFunctions _,
             Guid? arg)
-            => throw new InvalidOperationException(SqlServerStrings.FunctionOnClient(nameof(DataLength)));
+            => throw new InvalidOperationException(CoreStrings.FunctionOnClient(nameof(DataLength)));
     }
 }
diff --git a/src/EFCore.SqlServer/Query/Internal/SqlServerDataLengthFunctionTranslator.cs b/src/EFCore.SqlServer/Query/Internal/SqlServerDataLengthFunctionTranslator.cs
index 4a8660f920e..7915666a7e5 100644
--- a/src/EFCore.SqlServer/Query/Internal/SqlServerDataLengthFunctionTranslator.cs
+++ b/src/EFCore.SqlServer/Query/Internal/SqlServerDataLengthFunctionTranslator.cs
@@ -14,6 +14,8 @@ namespace Microsoft.EntityFrameworkCore.SqlServer.Query.Internal
 {
     public class SqlServerDataLengthFunctionTranslator : IMethodCallTranslator
     {
+        private static readonly List<string> _longReturningTypes = new List<string> { "nvarchar(max)", "varchar(max)", "varbinary(max)" };
+
         private static readonly HashSet<MethodInfo> _methodInfoDataLengthMapping
             = new HashSet<MethodInfo>
             {
@@ -68,6 +70,24 @@ public virtual SqlExpression Translate(SqlExpression instance, MethodInfo method
 
             if (_methodInfoDataLengthMapping.Contains(method))
             {
+                var argument = arguments[1];
+                if (argument.TypeMapping == null)
+                {
+                    argument = _sqlExpressionFactory.ApplyDefaultTypeMapping(argument);
+                }
+
+                if (_longReturningTypes.Contains(argument.TypeMapping.StoreType))
+                {
+                    var result = _sqlExpressionFactory.Function(
+                        "DATALENGTH",
+                        arguments.Skip(1),
+                        nullable: true,
+                        argumentsPropagateNullability: new[] { true },
+                        typeof(long));
+
+                    return _sqlExpressionFactory.Convert(result, method.ReturnType);
+                }
+
                 return _sqlExpressionFactory.Function(
                     "DATALENGTH",
                     arguments.Skip(1),
diff --git a/test/EFCore.SqlServer.FunctionalTests/Query/GearsOfWarQuerySqlServerTest.cs b/test/EFCore.SqlServer.FunctionalTests/Query/GearsOfWarQuerySqlServerTest.cs
index d30fafa4a1a..a7cb439b0d3 100644
--- a/test/EFCore.SqlServer.FunctionalTests/Query/GearsOfWarQuerySqlServerTest.cs
+++ b/test/EFCore.SqlServer.FunctionalTests/Query/GearsOfWarQuerySqlServerTest.cs
@@ -2,7 +2,10 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Linq;
 using System.Threading.Tasks;
+using Microsoft.EntityFrameworkCore.TestModels.GearsOfWarModel;
+using Xunit;
 using Xunit.Abstractions;
 
 namespace Microsoft.EntityFrameworkCore.Query
@@ -6976,6 +6979,20 @@ FROM [Gears] AS [g]
 ORDER BY [g].[Nickname]");
         }
 
+        [ConditionalTheory]
+        [MemberData(nameof(IsAsyncData))]
+        public async Task DataLength_function_for_string_parameter(bool async)
+        {
+            await AssertQueryScalar(
+                async,
+                ss => ss.Set<Mission>().Select(m => EF.Functions.DataLength(m.CodeName)),
+                ss => ss.Set<Mission>().Select(m => (int?)(m.CodeName.Length * 2)));
+
+            AssertSql(
+                @"SELECT CAST(DATALENGTH([m].[CodeName]) AS int)
+FROM [Missions] AS [m]");
+        }
+
         private void AssertSql(params string[] expected)
             => Fixture.TestSqlLoggerFactory.AssertBaseline(expected);
     }