diff --git a/scalalib/src/mill/scalalib/PublishModule.scala b/scalalib/src/mill/scalalib/PublishModule.scala
index 9626f1c28ce..0b7e52c8cc8 100644
--- a/scalalib/src/mill/scalalib/PublishModule.scala
+++ b/scalalib/src/mill/scalalib/PublishModule.scala
@@ -3,9 +3,9 @@ package scalalib
 
 import ammonite.ops._
 import mill.define.{ExternalModule, Task}
-import mill.eval.{PathRef, Result}
+import mill.eval.PathRef
 import mill.scalalib.publish.{Artifact, SonatypePublisher}
-import mill.util.Loose.Agg
+
 /**
   * Configuration necessary for publishing a Scala module to Maven Central or similar
   */
@@ -17,11 +17,11 @@ trait PublishModule extends JavaModule { outer =>
   def pomSettings: T[PomSettings]
   def publishVersion: T[String]
 
-  def publishSelfDependency = T{
-    Artifact(pomSettings().organization, artifactId(), publishVersion()),
+  def publishSelfDependency = T {
+    Artifact(pomSettings().organization, artifactId(), publishVersion())
   }
 
-  def publishXmlDeps = T.task{
+  def publishXmlDeps = T.task {
     val ivyPomDeps = ivyDeps().map(resolvePublishDependency().apply(_))
     val modulePomDeps = Task.sequence(moduleDeps.map(_.publishSelfDependency))()
     ivyPomDeps ++ modulePomDeps.map(Dependency(_, Scope.Compile))
@@ -59,7 +59,7 @@ trait PublishModule extends JavaModule { outer =>
 
   def sonatypeSnapshotUri: String = "https://oss.sonatype.org/content/repositories/snapshots"
 
-  def publishArtifacts = T{
+  def publishArtifacts = T {
     val baseName = s"${artifactId()}-${publishVersion()}"
     PublishModule.PublishData(
       artifactMetadata(),
@@ -73,20 +73,22 @@ trait PublishModule extends JavaModule { outer =>
   }
 
   def publish(sonatypeCreds: String,
-              gpgPassphrase: String,
+              gpgPassphrase: String = null,
+              signed: Boolean = true,
               release: Boolean): define.Command[Unit] = T.command {
     val PublishModule.PublishData(artifactInfo, artifacts) = publishArtifacts()
     new SonatypePublisher(
       sonatypeUri,
       sonatypeSnapshotUri,
       sonatypeCreds,
-      gpgPassphrase,
+      Option(gpgPassphrase),
+      signed,
       T.ctx().log
     ).publish(artifacts.map{case (a, b) => (a.path, b)}, artifactInfo, release)
   }
 }
 
-object PublishModule extends ExternalModule{
+object PublishModule extends ExternalModule {
   case class PublishData(meta: Artifact, payload: Seq[(PathRef, String)])
 
   object PublishData{
@@ -94,11 +96,12 @@ object PublishModule extends ExternalModule{
   }
 
   def publishAll(sonatypeCreds: String,
-                 gpgPassphrase: String,
+                 gpgPassphrase: String = null,
+                 signed: Boolean = true,
                  publishArtifacts: mill.main.Tasks[PublishModule.PublishData],
                  release: Boolean = false,
                  sonatypeUri: String = "https://oss.sonatype.org/service/local",
-                 sonatypeSnapshotUri: String = "https://oss.sonatype.org/content/repositories/snapshots") = T.command{
+                 sonatypeSnapshotUri: String = "https://oss.sonatype.org/content/repositories/snapshots") = T.command {
 
     val x: Seq[(Seq[(Path, String)], Artifact)] = Task.sequence(publishArtifacts.value)().map{
       case PublishModule.PublishData(a, s) => (s.map{case (p, f) => (p.path, f)}, a)
@@ -107,7 +110,8 @@ object PublishModule extends ExternalModule{
       sonatypeUri,
       sonatypeSnapshotUri,
       sonatypeCreds,
-      gpgPassphrase,
+      Option(gpgPassphrase),
+      signed,
       T.ctx().log
     ).publishAll(
       release,
diff --git a/scalalib/src/mill/scalalib/publish/SonatypePublisher.scala b/scalalib/src/mill/scalalib/publish/SonatypePublisher.scala
index 4f8f42b84f3..47ec8dbf1c4 100644
--- a/scalalib/src/mill/scalalib/publish/SonatypePublisher.scala
+++ b/scalalib/src/mill/scalalib/publish/SonatypePublisher.scala
@@ -11,7 +11,8 @@ import scalaj.http.HttpResponse
 class SonatypePublisher(uri: String,
                         snapshotUri: String,
                         credentials: String,
-                        gpgPassphrase: String,
+                        gpgPassphrase: Option[String],
+                        signed: Boolean,
                         log: Logger) {
 
   private val api = new SonatypeHttpApi(uri, credentials)
@@ -29,11 +30,11 @@ class SonatypePublisher(uri: String,
       ).mkString("/")
       val fileMapping = fileMapping0.map{ case (file, name) => (file, publishPath+"/"+name) }
 
-      val signedArtifacts = fileMapping ++ fileMapping.map {
+      val signedArtifacts = if (signed) fileMapping.map {
         case (file, name) => poorMansSign(file, gpgPassphrase) -> s"$name.asc"
-      }
+      } else Seq()
 
-      artifact -> signedArtifacts.flatMap {
+      artifact -> (fileMapping ++ signedArtifacts).flatMap {
         case (file, name) =>
           val content = read.bytes(file)
 
@@ -135,10 +136,15 @@ class SonatypePublisher(uri: String,
   }
 
   // http://central.sonatype.org/pages/working-with-pgp-signatures.html#signing-a-file
-  private def poorMansSign(file: Path, passphrase: String): Path = {
+  private def poorMansSign(file: Path, maybePassphrase: Option[String]): Path = {
     val fileName = file.toString
     import ammonite.ops.ImplicitWd._
-    %("gpg", "--passphrase", passphrase, "--batch", "--yes", "-a", "-b", fileName)
+    maybePassphrase match {
+      case Some(passphrase) =>
+        %("gpg", "--passphrase", passphrase, "--batch", "--yes", "-a", "-b", fileName)
+      case None =>
+        %("gpg", "--batch", "--yes", "-a", "-b", fileName)
+    }
     Path(fileName + ".asc")
   }