diff --git a/README.md b/README.md
index e3a0d13..3c90e84 100644
--- a/README.md
+++ b/README.md
@@ -60,7 +60,7 @@ MY_CERT="-----BEGIN CERTIFICATE-----
 Variable expansion of the form `$FOO` and `${FOO}` is supported based on the values in `.env` or the system environment.
 
 ### Change file name
-It is possible to change the file name `.env`
+It is possible to override the default file name `.env`. It will be treated as an absolute path if it starts with a `/`, and as a relative path to base directory of this project otherwise.
 ```
 ThisBuild  / envFileName := "dotenv"
 ```
diff --git a/src/main/scala/au/com/onegeek/sbtdotenv/SbtDotenv.scala b/src/main/scala/au/com/onegeek/sbtdotenv/SbtDotenv.scala
index fb2cf02..1f63cfe 100644
--- a/src/main/scala/au/com/onegeek/sbtdotenv/SbtDotenv.scala
+++ b/src/main/scala/au/com/onegeek/sbtdotenv/SbtDotenv.scala
@@ -84,9 +84,10 @@ object SbtDotenv extends AutoPlugin {
       fileName: String
   ): Option[Map[String, String]] = {
     val baseDirectory = state.configuration.baseDirectory
+    val filePath = if (fileName.startsWith("/")) fileName else s"${baseDirectory}/${fileName}"
     state.log.debug(s"Base directory: ${baseDirectory}")
-    state.log.debug(s"looking for .env file: ${baseDirectory}/${fileName}")
-    val dotEnvFile: File = new File(s"${baseDirectory}/${fileName}")
+    state.log.debug(s"looking for .env file: ${filePath}")
+    val dotEnvFile: File = new File(filePath)
     parseFile(dotEnvFile).map { environment =>
       state.log.info(
         s".env detected (fileName=${fileName}). About to configure JVM System Environment with new map"