diff --git a/src/Volo.Abp/System/Globalization/CultureHelper.cs b/src/Volo.Abp/System/Globalization/CultureHelper.cs
new file mode 100644
index 0000000000..dec84f768e
--- /dev/null
+++ b/src/Volo.Abp/System/Globalization/CultureHelper.cs
@@ -0,0 +1,33 @@
+using JetBrains.Annotations;
+using Volo;
+using Volo.Abp;
+
+namespace System.Globalization
+{
+    public static class CultureHelper
+    {
+        public static IDisposable Use([NotNull] string culture, string uiCulture = null)
+        {
+            Check.NotNull(culture, nameof(culture));
+
+            return Use(new CultureInfo(culture), uiCulture == null ? null : new CultureInfo(uiCulture));
+        }
+
+        public static IDisposable Use([NotNull] CultureInfo culture, CultureInfo uiCulture = null)
+        {
+            Check.NotNull(culture, nameof(culture));
+
+            var currentCulture = CultureInfo.CurrentCulture;
+            var currentUiCulture = CultureInfo.CurrentUICulture;
+
+            CultureInfo.CurrentCulture = culture;
+            CultureInfo.CurrentCulture = uiCulture ?? culture;
+
+            return new DisposeAction(() =>
+            {
+                CultureInfo.CurrentCulture = currentCulture;
+                CultureInfo.CurrentUICulture = currentUiCulture;
+            });
+        }
+    }
+}
diff --git a/src/Volo.ExtensionMethods/Volo/ExtensionMethods/StringExtensions.cs b/src/Volo.ExtensionMethods/Volo/ExtensionMethods/StringExtensions.cs
index 7c0faf9da6..a95f31963a 100644
--- a/src/Volo.ExtensionMethods/Volo/ExtensionMethods/StringExtensions.cs
+++ b/src/Volo.ExtensionMethods/Volo/ExtensionMethods/StringExtensions.cs
@@ -6,8 +6,6 @@ using Volo.ExtensionMethods.Collections.Generic;
 
 namespace Volo.ExtensionMethods
 {
-    //TODO: Not working properly with cultures!
-
     /// <summary>
     /// Extension methods for String class.
     /// </summary>
@@ -16,15 +14,7 @@ namespace Volo.ExtensionMethods
         /// <summary>
         /// Adds a char to end of given string if it does not ends with the char.
         /// </summary>
-        public static string EnsureEndsWith(this string str, char c)
-        {
-            return EnsureEndsWith(str, c, StringComparison.Ordinal);
-        }
-
-        /// <summary>
-        /// Adds a char to end of given string if it does not ends with the char.
-        /// </summary>
-        public static string EnsureEndsWith(this string str, char c, StringComparison comparisonType)
+        public static string EnsureEndsWith(this string str, char c, StringComparison comparisonType = StringComparison.Ordinal)
         {
             Check.NotNull(str, nameof(str));
 
@@ -36,19 +26,10 @@ namespace Volo.ExtensionMethods
             return str + c;
         }
 
-
-        /// <summary>
-        /// Adds a char to beginning of given string if it does not starts with the char.
-        /// </summary>
-        public static string EnsureStartsWith(this string str, char c)
-        {
-            return EnsureStartsWith(str, c, StringComparison.Ordinal);
-        }
-
         /// <summary>
         /// Adds a char to beginning of given string if it does not starts with the char.
         /// </summary>
-        public static string EnsureStartsWith(this string str, char c, StringComparison comparisonType)
+        public static string EnsureStartsWith(this string str, char c, StringComparison comparisonType = StringComparison.Ordinal)
         {
             Check.NotNull(str, nameof(str));
 
@@ -239,8 +220,9 @@ namespace Volo.ExtensionMethods
         /// Converts PascalCase string to camelCase string.
         /// </summary>
         /// <param name="str">String to convert</param>
+        /// <param name="useCurrentCulture">set true to use current culture. Otherwise, invariant culture will be used.</param>
         /// <returns>camelCase of the string</returns>
-        public static string ToCamelCase(this string str)
+        public static string ToCamelCase(this string str, bool useCurrentCulture = false)
         {
             if (string.IsNullOrWhiteSpace(str))
             {
@@ -249,10 +231,10 @@ namespace Volo.ExtensionMethods
 
             if (str.Length == 1)
             {
-                return str.ToLower();
+                return useCurrentCulture ? str.ToLower() : str.ToLowerInvariant();
             }
 
-            return char.ToLower(str[0]) + str.Substring(1);
+            return (useCurrentCulture ? char.ToLower(str[0]) : char.ToLowerInvariant(str[0])) + str.Substring(1);
         }
 
         /// <summary>
@@ -260,14 +242,17 @@ namespace Volo.ExtensionMethods
         /// Example: "ThisIsSampleSentence" is converted to "This is a sample sentence".
         /// </summary>
         /// <param name="str">String to convert.</param>
-        public static string ToSentenceCase(this string str)
+        /// <param name="useCurrentCulture">set true to use current culture. Otherwise, invariant culture will be used.</param>
+        public static string ToSentenceCase(this string str, bool useCurrentCulture = false)
         {
             if (string.IsNullOrWhiteSpace(str))
             {
                 return str;
             }
 
-            return Regex.Replace(str, "[a-z][A-Z]", m => m.Value[0] + " " + char.ToLower(m.Value[1]));
+            return useCurrentCulture
+                ? Regex.Replace(str, "[a-z][A-Z]", m => m.Value[0] + " " + char.ToLower(m.Value[1]))
+                : Regex.Replace(str, "[a-z][A-Z]", m => m.Value[0] + " " + char.ToLowerInvariant(m.Value[1]));
         }
 
         /// <summary>
@@ -318,8 +303,9 @@ namespace Volo.ExtensionMethods
         /// Converts camelCase string to PascalCase string.
         /// </summary>
         /// <param name="str">String to convert</param>
+        /// <param name="useCurrentCulture">set true to use current culture. Otherwise, invariant culture will be used.</param>
         /// <returns>PascalCase of the string</returns>
-        public static string ToPascalCase(this string str)
+        public static string ToPascalCase(this string str, bool useCurrentCulture = false)
         {
             if (string.IsNullOrWhiteSpace(str))
             {
@@ -328,10 +314,10 @@ namespace Volo.ExtensionMethods
 
             if (str.Length == 1)
             {
-                return str.ToUpper();
+                return useCurrentCulture ? str.ToUpper() : str.ToUpperInvariant();
             }
 
-            return char.ToUpper(str[0]) + str.Substring(1);
+            return (useCurrentCulture ? char.ToUpper(str[0]) : char.ToUpperInvariant(str[0])) + str.Substring(1);
         }
 
         /// <summary>
diff --git a/test/Volo.ExtensionMethods.Tests/Volo/ExtensionMethods/StringExtensions_Tests.cs b/test/Volo.ExtensionMethods.Tests/Volo/ExtensionMethods/StringExtensions_Tests.cs
index 109c00e718..c2d8d302fe 100644
--- a/test/Volo.ExtensionMethods.Tests/Volo/ExtensionMethods/StringExtensions_Tests.cs
+++ b/test/Volo.ExtensionMethods.Tests/Volo/ExtensionMethods/StringExtensions_Tests.cs
@@ -1,16 +1,17 @@
-using System.Globalization;
+using System;
+using System.Globalization;
 using Shouldly;
 using Xunit;
 
 namespace Volo.ExtensionMethods
 {
-    public class StringExtensions_Tests
+    public class StringExtensions_Tests : IDisposable
     {
+        private readonly IDisposable _cultureScope;
+
         public StringExtensions_Tests()
         {
-            //TODO: Temporary workaround! See StringExtensions
-            CultureInfo.CurrentUICulture = new CultureInfo("en-US");
-            CultureInfo.CurrentCulture = new CultureInfo("en-US");
+            _cultureScope = CultureHelper.Use("en-US");
         }
 
         [Fact]
@@ -21,11 +22,21 @@ namespace Volo.ExtensionMethods
             "Test!".EnsureEndsWith('!').ShouldBe("Test!");
             @"C:\test\folderName".EnsureEndsWith('\\').ShouldBe(@"C:\test\folderName\");
             @"C:\test\folderName\".EnsureEndsWith('\\').ShouldBe(@"C:\test\folderName\");
+            "Sarı".EnsureEndsWith('ı').ShouldBe("Sarı");
 
             //Case differences
             "TurkeY".EnsureEndsWith('y').ShouldBe("TurkeYy");
         }
 
+        [Fact]
+        public void EnsureEndsWith_CultureSpecific_Test()
+        {
+            using (CultureHelper.Use("tr-TR"))
+            {
+                "Kırmızı".EnsureEndsWith('I', StringComparison.CurrentCultureIgnoreCase).ShouldBe("Kırmızı");
+            }
+        }
+
         [Fact]
         public void EnsureStartsWith_Test()
         {
@@ -45,6 +56,15 @@ namespace Volo.ExtensionMethods
             "istanbul".ToPascalCase().ShouldBe("Istanbul");
         }
 
+        [Fact]
+        public void ToPascalCase_CurrentCulture_Test()
+        {
+            using (CultureHelper.Use("tr-TR"))
+            {
+                "istanbul".ToPascalCase(true).ShouldBe("İstanbul");
+            }
+        }
+
         [Fact]
         public void ToCamelCase_Test()
         {
@@ -173,5 +193,10 @@ namespace Volo.ExtensionMethods
             MyValue1,
             MyValue2
         }
+
+        public void Dispose()
+        {
+            _cultureScope.Dispose();
+        }
     }
 }
\ No newline at end of file