diff --git a/DESCRIPTION b/DESCRIPTION
index 7ceff712..f018bcc8 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -10,8 +10,8 @@ Authors@R: c(
 Description: The ability to tune models is important. 'tune' contains
     functions and classes to be used in conjunction with other
     'tidymodels' packages for finding reasonable values of
-    hyper-parameters in models, preprocessing methods, and
-    post-processing steps.
+    hyper-parameters in models, preprocessing methods, and post-processing
+    steps.
 License: MIT + file LICENSE
 URL: https://tune.tidymodels.org/, https://github.com/tidymodels/tune
 BugReports: https://github.com/tidymodels/tune/issues
@@ -21,11 +21,12 @@ Imports:
     cli (>= 3.3.0),
     dials (>= 1.3.0.9000),
     dplyr (>= 1.1.0),
+    GauPro (>= 0.2.15),
     generics (>= 0.1.2),
     ggplot2,
     glue (>= 1.6.2),
-    GauPro (>= 0.2.15),
     hardhat (>= 1.4.2),
+    lifecycle,
     parallel,
     parsnip (>= 1.4.1.9002),
     purrr (>= 1.0.0),
diff --git a/NEWS.md b/NEWS.md
index 88281ac9..de8c10cc 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,7 @@
 # tune (development version)
 
+* `finalize_workflow_preprocessor()` is deprecated (#1157).
+
 * Model tuning has been enabled for quantile regression models. (#1125)
 
 * In `tune_grid()`, a bug was fixed that caused inefficiency where preprocessing steps were applied to data being predicted several times (redundantly). We now execute that operation once. (#1101)
diff --git a/R/grid_helpers.R b/R/grid_helpers.R
index c64747fa..32c593b7 100644
--- a/R/grid_helpers.R
+++ b/R/grid_helpers.R
@@ -114,7 +114,13 @@ has_metrics_by <- function(metrics_by) {
 
 #' @export
 #' @rdname tune-internal-functions
+#' @description
+#' `r lifecycle::badge("deprecated")`
+#'
+#' `finalize_workflow_preprocessor()` is deprecated.
 finalize_workflow_preprocessor <- function(workflow, grid_preprocessor) {
+  lifecycle::deprecate_warn("2.1.0", "finalize_workflow_preprocessor()")
+
   # Already finalized, nothing to tune
   if (ncol(grid_preprocessor) == 0L) {
     return(workflow)
diff --git a/man/tune-internal-functions.Rd b/man/tune-internal-functions.Rd
index 7107176c..01ee44a5 100644
--- a/man/tune-internal-functions.Rd
+++ b/man/tune-internal-functions.Rd
@@ -67,6 +67,10 @@ always unique and do not represent a tuning "issue" can bypass the cataloger
 by setting \code{catalog = FALSE}.}
 }
 \description{
+\ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}}
+
+\code{finalize_workflow_preprocessor()} is deprecated.
+
 These are not to be meant to be invoked directly by users.
 }
 \keyword{internal}
diff --git a/tests/testthat/_snaps/grid.md b/tests/testthat/_snaps/grid.md
index 4479b56b..1920e758 100644
--- a/tests/testthat/_snaps/grid.md
+++ b/tests/testthat/_snaps/grid.md
@@ -65,3 +65,11 @@
        9 <split [29/3]> Fold09 <tibble [6 x 5]> <tibble [0 x 4]>
       10 <split [29/3]> Fold10 <tibble [6 x 5]> <tibble [0 x 4]>
 
+# finalize_workflow_preprocessor() is deprecated
+
+    Code
+      wflow <- finalize_workflow_preprocessor(wflow, grid)
+    Condition
+      Warning:
+      `finalize_workflow_preprocessor()` was deprecated in tune 2.1.0.
+
diff --git a/tests/testthat/test-grid.R b/tests/testthat/test-grid.R
index 19f64495..5618b2dc 100644
--- a/tests/testthat/test-grid.R
+++ b/tests/testthat/test-grid.R
@@ -787,3 +787,12 @@ test_that("retain extra attributes", {
   expect_null(attr(res, "workflow"))
   expect_true(inherits(attr(res2, "workflow"), "workflow"))
 })
+
+test_that("finalize_workflow_preprocessor() is deprecated", {
+  helper_objects <- helper_objects_tune()
+  wflow <- workflow() |>
+    add_recipe(helper_objects$rec_tune_1) |>
+    add_model(helper_objects$lm_mod)
+  grid <- tibble::tibble(num_comp = 1L)
+  expect_snapshot(wflow <- finalize_workflow_preprocessor(wflow, grid))
+})