diff --git a/src/compiler/crystal/tools/dependencies.cr b/src/compiler/crystal/tools/dependencies.cr
index cfb26fbccc43..becd64b26d73 100644
--- a/src/compiler/crystal/tools/dependencies.cr
+++ b/src/compiler/crystal/tools/dependencies.cr
@@ -8,8 +8,8 @@ class Crystal::Command
 
     dependency_printer = DependencyPrinter.create(STDOUT, format: DependencyPrinter::Format.parse(config.output_format), verbose: config.verbose)
 
-    dependency_printer.includes.concat config.includes.map { |path| ::Path[path].expand.to_s }
-    dependency_printer.excludes.concat config.excludes.map { |path| ::Path[path].expand.to_s }
+    dependency_printer.includes.concat config.includes.map { |path| ::Path[path].expand.to_posix.to_s }
+    dependency_printer.excludes.concat config.excludes.map { |path| ::Path[path].expand.to_posix.to_s }
     config.compiler.dependency_printer = dependency_printer
 
     dependency_printer.start_format