diff --git a/src/Testcontainers/Configurations/IOperatingSystem.cs b/src/Testcontainers/Configurations/IOperatingSystem.cs
index 5c99cda38..c67293c54 100644
--- a/src/Testcontainers/Configurations/IOperatingSystem.cs
+++ b/src/Testcontainers/Configurations/IOperatingSystem.cs
@@ -19,6 +19,6 @@ public interface IOperatingSystem
     /// <param name="path">Path to normalize.</param>
     /// <returns>Normalized path.</returns>
     [PublicAPI]
-    string NormalizePath(string path);
+    string NormalizePath([CanBeNull] string path);
   }
 }
diff --git a/src/Testcontainers/Configurations/Images/ImageFromDockerfileConfiguration.cs b/src/Testcontainers/Configurations/Images/ImageFromDockerfileConfiguration.cs
index a1057deb2..5e4b6842f 100644
--- a/src/Testcontainers/Configurations/Images/ImageFromDockerfileConfiguration.cs
+++ b/src/Testcontainers/Configurations/Images/ImageFromDockerfileConfiguration.cs
@@ -6,6 +6,8 @@ namespace DotNet.Testcontainers.Configurations
   /// <inheritdoc cref="IImageFromDockerfileConfiguration" />
   internal sealed class ImageFromDockerfileConfiguration : DockerResourceConfiguration, IImageFromDockerfileConfiguration
   {
+    private static readonly IOperatingSystem OS = new Unix();
+
     /// <summary>
     /// Initializes a new instance of the <see cref="ImageFromDockerfileConfiguration" /> class.
     /// </summary>
@@ -36,8 +38,8 @@ public ImageFromDockerfileConfiguration(
       : base(dockerEndpointAuthenticationConfiguration, labels)
     {
       this.Image = image;
-      this.Dockerfile = dockerfile;
-      this.DockerfileDirectory = dockerfileDirectory;
+      this.Dockerfile = OS.NormalizePath(dockerfile);
+      this.DockerfileDirectory = OS.NormalizePath(dockerfileDirectory);
       this.DeleteIfExists = deleteIfExists;
       this.BuildArguments = buildArguments;
     }
diff --git a/src/Testcontainers/Configurations/Unix.cs b/src/Testcontainers/Configurations/Unix.cs
index e34247b8b..59b083e7a 100644
--- a/src/Testcontainers/Configurations/Unix.cs
+++ b/src/Testcontainers/Configurations/Unix.cs
@@ -55,7 +55,7 @@ public Unix(IDockerEndpointAuthenticationConfiguration dockerEndpointAuthConfig)
     /// <inheritdoc />
     public string NormalizePath(string path)
     {
-      return path.Replace('\\', '/');
+      return path?.Replace('\\', '/');
     }
   }
 }
diff --git a/src/Testcontainers/Configurations/Windows.cs b/src/Testcontainers/Configurations/Windows.cs
index 0b58e636d..c280efe8b 100644
--- a/src/Testcontainers/Configurations/Windows.cs
+++ b/src/Testcontainers/Configurations/Windows.cs
@@ -55,7 +55,7 @@ public Windows(IDockerEndpointAuthenticationConfiguration dockerEndpointAuthConf
     /// <inheritdoc />
     public string NormalizePath(string path)
     {
-      return path.Replace('/', '\\');
+      return path?.Replace('/', '\\');
     }
   }
 }