diff --git a/Creek.FileRepository/Helpers/StringHelper.cs b/Creek.FileRepository/Helpers/StringHelper.cs
new file mode 100644
index 0000000..82e235b
--- /dev/null
+++ b/Creek.FileRepository/Helpers/StringHelper.cs
@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Creek.FileRepository.Helpers
+{
+    internal class StringHelper
+    {
+        public static bool IsInvalidFileName(string filename)
+        {
+            char[] invalidCharacters = new char[] { '<', '>', ':', '\'', '/', '\\', '|', '?', '*' };
+
+            return Array.Exists(invalidCharacters, character => filename.Contains(character.ToString()));
+        }
+
+        internal static string MakeValidFileName(string originalFileName)
+        {
+            char[] invalids = System.IO.Path.GetInvalidFileNameChars();
+            string validFileName = String.Join("_", originalFileName.Split(invalids, StringSplitOptions.RemoveEmptyEntries)).TrimEnd('.');
+
+            // Additionally remove Windows characters explicitly, in case we're running on Linux (e.g. in Docker) but need to access the files in Windows
+            string[] charsToRemove = new string[] { "<", ">", ":", "\"", "/", "\\", "|", "?", "*" };
+
+            validFileName = RemoveCharsFromString(charsToRemove, validFileName);
+
+            return validFileName;
+        }
+
+        internal static string RemoveCharsFromString(string[] charsToRemove, string str)
+        {
+            foreach (string c in charsToRemove)
+            {
+                str = str.Replace(c, string.Empty);
+            }
+
+            return str;
+        }
+    }
+}
diff --git a/Creek.FileRepository/Repositories/SftpRepository.cs b/Creek.FileRepository/Repositories/SftpRepository.cs
index 76dc630..0f4aeba 100644
--- a/Creek.FileRepository/Repositories/SftpRepository.cs
+++ b/Creek.FileRepository/Repositories/SftpRepository.cs
@@ -1,4 +1,5 @@
-using Creek.FileRepository.Models;
+using Creek.FileRepository.Helpers;
+using Creek.FileRepository.Models;
 using Microsoft.Extensions.Configuration;
 using Renci.SshNet;
 using Renci.SshNet.Sftp;
@@ -40,6 +41,11 @@ namespace Creek.FileRepository.Repositories
         /// <returns>Returns the filename.</returns>
         public async Task<string> CreateFileAsync(RepoFile file)
         {
+            if (StringHelper.IsInvalidFileName(file.Filename))
+            {
+                throw new ArgumentException($"The filename for'{nameof(file)}' contains invalid characters for a filename.", nameof(file));
+            }
+
             bool canOverride = false;
             this.UploadFile(file, canOverride);
 
@@ -57,6 +63,10 @@ namespace Creek.FileRepository.Repositories
             {
                 throw new ArgumentException($"'{nameof(filename)}' cannot be null or empty.", nameof(filename));
             }
+            else if (StringHelper.IsInvalidFileName(filename))
+            {
+                throw new ArgumentException($"'{nameof(filename)}' contains invalid characters for a filename.", nameof(filename));
+            }
 
             using (var client = new SftpClient(this.host, this.port == 0 ? 22 : this.port, this.username, this.password))
             {
@@ -91,6 +101,10 @@ namespace Creek.FileRepository.Repositories
             {
                 throw new ArgumentException($"'{nameof(filename)}' cannot be null or empty.", nameof(filename));
             }
+            else if (StringHelper.IsInvalidFileName(filename))
+            {
+                throw new ArgumentException($"'{nameof(filename)}' contains invalid characters for a filename.", nameof(filename));
+            }
 
             RepoFile repoFile = new RepoFile();
             repoFile.Content = new System.IO.MemoryStream();
@@ -128,6 +142,11 @@ namespace Creek.FileRepository.Repositories
         /// <returns>Returns true if update was successful.</returns>
         public async Task<bool> UpdateFileAsync(RepoFile file)
         {
+            if (StringHelper.IsInvalidFileName(file.Filename))
+            {
+                throw new ArgumentException($"The filename for'{nameof(file)}' contains invalid characters for a filename.", nameof(file));
+            }
+
             bool canOverride = true;
             this.UploadFile(file, canOverride);
 
diff --git a/UnitTests/SftpRepositoryShould.cs b/UnitTests/SftpRepositoryShould.cs
index 6b1f8a9..cf0b52f 100644
--- a/UnitTests/SftpRepositoryShould.cs
+++ b/UnitTests/SftpRepositoryShould.cs
@@ -20,6 +20,12 @@ namespace UnitTests
         {
         }
 
+        [Test]
+        public async Task ShouldNotCreateAFileWithAnInvalidFilename()
+        {
+            Assert.That(() => CreateTestFile("create><invalid?/test.txt"), Throws.TypeOf<ArgumentException>());
+        }
+
         [Test]
         public async Task ShouldCreateAFileWithoutThrowing()
         {