diff --git a/main/src/main/scala/sbt/BuildPaths.scala b/main/src/main/scala/sbt/BuildPaths.scala
index ba4219615..064f50107 100644
--- a/main/src/main/scala/sbt/BuildPaths.scala
+++ b/main/src/main/scala/sbt/BuildPaths.scala
@@ -8,6 +8,7 @@
 package sbt
 
 import java.io.File
+import java.util.Locale
 import KeyRanks.DSetting
 
 import sbt.io.{ GlobFilter, Path }
@@ -114,7 +115,9 @@ object BuildPaths {
   private[this] def defaultDependencyBase(globalBase: File) = globalBase / "dependency"
   private[this] def defaultGlobalZinc(globalBase: File) = globalBase / "zinc"
 
-  def configurationSources(base: File): Seq[File] = (base * (GlobFilter("*.sbt") - ".sbt")).get
+  def configurationSources(base: File): Seq[File] =
+    (base * (GlobFilter("*.sbt") - ".sbt")).get
+      .sortBy(_.getName.toLowerCase(Locale.ENGLISH))
   def pluginDirectory(definitionBase: File) = definitionBase / PluginsDirectoryName
 
   def evalOutputDirectory(base: File) = outputDirectory(base) / "config-classes"
diff --git a/sbt/src/sbt-test/project/setting-order/a.sbt b/sbt/src/sbt-test/project/setting-order/a.sbt
new file mode 100644
index 000000000..02cd89214
--- /dev/null
+++ b/sbt/src/sbt-test/project/setting-order/a.sbt
@@ -0,0 +1 @@
+Compile / scalacOptions += "a"
diff --git a/sbt/src/sbt-test/project/setting-order/b.sbt b/sbt/src/sbt-test/project/setting-order/b.sbt
new file mode 100644
index 000000000..e2ae0f78a
--- /dev/null
+++ b/sbt/src/sbt-test/project/setting-order/b.sbt
@@ -0,0 +1 @@
+Compile / scalacOptions += "b"
diff --git a/sbt/src/sbt-test/project/setting-order/build.sbt b/sbt/src/sbt-test/project/setting-order/build.sbt
new file mode 100644
index 000000000..69d74540d
--- /dev/null
+++ b/sbt/src/sbt-test/project/setting-order/build.sbt
@@ -0,0 +1,12 @@
+val check = taskKey[Unit]("")
+
+lazy val root = (project in file("."))
+  .settings(
+    Compile / scalacOptions += "multi-project",
+    check := {
+      val xs = (Compile / scalacOptions).value
+      assert(xs.toList == List("multi-project", "a", "b", "bare", "c"), s"$xs")
+    }
+  )
+
+Compile / scalacOptions += "bare"
diff --git a/sbt/src/sbt-test/project/setting-order/c.sbt b/sbt/src/sbt-test/project/setting-order/c.sbt
new file mode 100644
index 000000000..07a70ce8d
--- /dev/null
+++ b/sbt/src/sbt-test/project/setting-order/c.sbt
@@ -0,0 +1 @@
+Compile / scalacOptions += "c"
diff --git a/sbt/src/sbt-test/project/setting-order/test b/sbt/src/sbt-test/project/setting-order/test
new file mode 100644
index 000000000..15675b169
--- /dev/null
+++ b/sbt/src/sbt-test/project/setting-order/test
@@ -0,0 +1 @@
+> check