diff --git a/src/app/FakeLib/FSIHelper.fs b/src/app/FakeLib/FSIHelper.fs
index 3f130443ffe..1bd96ca09ca 100644
--- a/src/app/FakeLib/FSIHelper.fs
+++ b/src/app/FakeLib/FSIHelper.fs
@@ -3,8 +3,11 @@ module Fake.FSIHelper
    
 /// The Path to the F# interactive tool
 let fsiPath = 
-    let ev = environVar "FSI"
-    if not (isNullOrEmpty ev) then ev else findPath "FSIPath" "fsi.exe"
+    if System.Environment.OSVersion.Platform = System.PlatformID.Unix then
+        "fsi"
+    else
+        let ev = environVar "FSI"
+        if not (isNullOrEmpty ev) then ev else findPath "FSIPath" "fsi.exe"
       
 /// Run the given buildscript with fsi.exe
 let runBuildScript printDetails script args = 
@@ -27,4 +30,4 @@ let runBuildScript printDetails script args =
         setVar("FSI",fsiPath)) System.TimeSpan.MaxValue
     
     System.Threading.Thread.Sleep 1000
-    result
\ No newline at end of file
+    result