diff --git a/NEWS.md b/NEWS.md
index f9f2df20..3ffe925d 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,8 @@
 # dials (development version)
 
+* `regularization_factor()` is now exclusive of the lower border 0 in compliance with `ranger::ranger()` (#381).
+
+
 # dials 1.4.0
 
 * For space-filling designs for $p$ parameters, there is a higher likelihood of finding a space-filling design for `1 < size <= p`. Also, single-point designs now default to a random grid (#363).
diff --git a/R/param_engine_ranger.R b/R/param_engine_ranger.R
index 137dc392..b56308dc 100644
--- a/R/param_engine_ranger.R
+++ b/R/param_engine_ranger.R
@@ -23,7 +23,7 @@ regularization_factor <- function(range = c(0, 1), trans = NULL) {
   new_quant_param(
     type = "double",
     range = range,
-    inclusive = c(TRUE, TRUE),
+    inclusive = c(FALSE, TRUE),
     trans = trans,
     label = c(regularization_factor = "Gain Penalization"),
     finalize = NULL