diff --git a/lib/asciidoctor/git-blob-include-processor/README.adoc b/lib/asciidoctor/git-blob-include-processor/README.adoc
index 6dfbe75..4e81054 100644
--- a/lib/asciidoctor/git-blob-include-processor/README.adoc
+++ b/lib/asciidoctor/git-blob-include-processor/README.adoc
@@ -23,6 +23,9 @@ If the resulting operation ends in an error (i.e., non-existing revision, file,
 
 == Attributes
 
+- `gitrepo` is the path to the Git repo.
+By default, it is the base directory of the document.
+
 - `path` is the filepath to be retrieved from the revision.
 When used with `diff`, it changes into a semicolon-delimited (`;`) list of files to make diffs with multiple files.
 
diff --git a/lib/asciidoctor/git-blob-include-processor/extension.rb b/lib/asciidoctor/git-blob-include-processor/extension.rb
index 0ea2040..a8301c0 100644
--- a/lib/asciidoctor/git-blob-include-processor/extension.rb
+++ b/lib/asciidoctor/git-blob-include-processor/extension.rb
@@ -8,7 +8,8 @@ class GitBlobIncludeProcessor < Asciidoctor::Extensions::IncludeProcessor
   end
 
   def process(doc, reader, target, attrs)
-    repo = Rugged::Repository.discover(__dir__)
+    attrs['gitrepo'] ||= doc.base_dir
+    repo = Rugged::Repository.discover(attrs['gitrepo'])
 
     git_object_ref = target.delete_prefix 'git:'
     git_object_ref = doc.attributes['doccontentref'] if git_object_ref.empty?