diff --git a/main-command/src/main/scala/sbt/internal/client/NetworkClient.scala b/main-command/src/main/scala/sbt/internal/client/NetworkClient.scala
index d6b376dac..d9514a323 100644
--- a/main-command/src/main/scala/sbt/internal/client/NetworkClient.scala
+++ b/main-command/src/main/scala/sbt/internal/client/NetworkClient.scala
@@ -1045,7 +1045,8 @@ object NetworkClient {
   private[client] val noStdErr = "--no-stderr"
   private[client] val sbtBase = "--sbt-base-directory"
   private[client] def parseArgs(args: Array[String]): Arguments = {
-    var sbtScript = if (Properties.isWin) "sbt.bat" else "sbt"
+    val defaultSbtScript = if (Properties.isWin) "sbt.bat" else "sbt"
+    var sbtScript = Properties.propOrNone("sbt.script")
     var launchJar: Option[String] = None
     var bsp = false
     val commandArgs = new mutable.ArrayBuffer[String]
@@ -1067,11 +1068,10 @@ object NetworkClient {
           sbtScript = a
             .split("--sbt-script=")
             .lastOption
-            .map(_.replaceAllLiterally("%20", " "))
-            .getOrElse(sbtScript)
+            .orElse(sbtScript)
         case "--sbt-script" if i + 1 < sanitized.length =>
           i += 1
-          sbtScript = sanitized(i).replaceAllLiterally("%20", " ")
+          sbtScript = Some(sanitized(i))
         case a if a.startsWith("--sbt-launch-jar=") =>
           launchJar = a
             .split("--sbt-launch-jar=")
@@ -1091,12 +1091,17 @@ object NetworkClient {
     }
     val base = new File("").getCanonicalFile
     if (!sbtArguments.contains("-Dsbt.io.virtual=true")) sbtArguments += "-Dsbt.io.virtual=true"
+    if (!sbtArguments.exists(_.startsWith("-Dsbt.script"))) {
+      sbtScript.foreach { sbtScript =>
+        sbtArguments += s"-Dsbt.script=$sbtScript"
+      }
+    }
     new Arguments(
       base,
       sbtArguments.toSeq,
       commandArgs.toSeq,
       completionArguments.toSeq,
-      sbtScript,
+      sbtScript.getOrElse(defaultSbtScript).replaceAllLiterally("%20", " "),
       bsp,
       launchJar
     )
diff --git a/protocol/src/main/scala/sbt/internal/bsp/BuildServerConnection.scala b/protocol/src/main/scala/sbt/internal/bsp/BuildServerConnection.scala
index 9b21dd31e..9ee2da80c 100644
--- a/protocol/src/main/scala/sbt/internal/bsp/BuildServerConnection.scala
+++ b/protocol/src/main/scala/sbt/internal/bsp/BuildServerConnection.scala
@@ -7,12 +7,13 @@
 
 package sbt.internal.bsp
 
-import java.io.File
-
-import sbt.internal.bsp
+import sbt.internal.bsp.codec.JsonProtocol.BspConnectionDetailsFormat
 import sbt.io.IO
 import sjsonnew.support.scalajson.unsafe.{ CompactPrinter, Converter }
 
+import java.io.File
+import java.nio.file.{ Files, Paths }
+
 object BuildServerConnection {
   final val name = "sbt"
   final val bspVersion = "2.0.0-M5"
@@ -21,26 +22,45 @@ object BuildServerConnection {
   private final val SbtLaunchJar = "sbt-launch(-.*)?\\.jar".r
 
   private[sbt] def writeConnectionFile(sbtVersion: String, baseDir: File): Unit = {
-    import bsp.codec.JsonProtocol._
     val bspConnectionFile = new File(baseDir, ".bsp/sbt.json")
-    val javaHome = System.getProperty("java.home")
-    val classPath = System.getProperty("java.class.path")
-    val sbtLaunchJar = classPath
-      .split(File.pathSeparator)
-      .find(jar => SbtLaunchJar.findFirstIn(jar).nonEmpty)
-      .map(_.replaceAllLiterally(" ", "%20"))
-    val argv =
-      Vector(
-        s"$javaHome/bin/java",
-        "-Xms100m",
-        "-Xmx100m",
-        "-classpath",
-        classPath,
-        "xsbt.boot.Boot",
-        "-bsp"
-      ) ++ sbtLaunchJar.map(jar => s"--sbt-launch-jar=$jar")
+    val argv = Option(System.getProperty("sbt.script"))
+      .map(_.replaceAllLiterally("%20", " "))
+      .orElse(sbtScriptInPath) match {
+      case Some(sbtScript) =>
+        Vector(sbtScript, "-bsp", s"-Dsbt.script=${sbtScript.replaceAllLiterally(" ", "%20")}")
+      case None =>
+        // IntelliJ can start sbt even if the sbt script is not accessible from $PATH.
+        // To do so it uses its own bundled sbt-launch.jar.
+        // In that case, we must pass the path of the sbt-launch.jar to the BSP connection
+        // so that the server can be started.
+        // A known problem in that situation is that the .sbtopts and .jvmopts are not loaded.
+        val javaHome = System.getProperty("java.home")
+        val classPath = System.getProperty("java.class.path")
+        val sbtLaunchJar = classPath
+          .split(File.pathSeparator)
+          .find(jar => SbtLaunchJar.findFirstIn(jar).nonEmpty)
+          .map(_.replaceAllLiterally(" ", "%20"))
+
+        Vector(
+          s"$javaHome/bin/java",
+          "-Xms100m",
+          "-Xmx100m",
+          "-classpath",
+          classPath,
+          "xsbt.boot.Boot",
+          "-bsp"
+        ) ++ sbtLaunchJar.map(jar => s"--sbt-launch-jar=$jar")
+    }
     val details = BspConnectionDetails(name, sbtVersion, bspVersion, languages, argv)
     val json = Converter.toJson(details).get
     IO.write(bspConnectionFile, CompactPrinter(json), append = false)
   }
+
+  private def sbtScriptInPath: Option[String] = {
+    // For those who use an old sbt script, the -Dsbt.script is not set
+    // As a fallback we try to find the sbt script in $PATH
+    val envPath = Option(System.getenv("PATH")).getOrElse("")
+    val allPaths = envPath.split(File.pathSeparator).map(Paths.get(_))
+    allPaths.map(_.resolve("sbt")).find(Files.exists(_)).map(_.toString)
+  }
 }
diff --git a/sbt b/sbt
index 8adff2117..990515d6c 100755
--- a/sbt
+++ b/sbt
@@ -299,6 +299,16 @@ addDefaultMemory() {
   fi
 }
 
+addSbtScriptProperty () {
+  if [[ "${java_args[@]}" == -Dsbt.script=* ]]; then
+    :
+  else
+    sbt_script=$0
+    sbt_script=${sbt_script/ /%20}
+    addJava "-Dsbt.script=$sbt_script"
+  fi
+}
+
 require_arg () {
   local type="$1"
   local opt="$2"
@@ -769,6 +779,7 @@ else
   java_version="$(jdk_version)"
   vlog "[process_args] java_version = '$java_version'"
   addDefaultMemory
+  addSbtScriptProperty
   set -- "${residual_args[@]}"
   argumentCount=$#
   run