diff --git a/NEWS.md b/NEWS.md
index b223f663..7589d3aa 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,6 @@
 # bayesplot (development version)
 
+* Standardize input validation errors in `ppc_km_overlay()` and interpolation helpers to use `rlang::abort()` for consistent error handling.
 * Fix assignment-in-call bug in `mcmc_rank_ecdf()` (#).
 * Replaced deprecated `dplyr` and `tidyselect` functions (`top_n`, `one_of`, `group_indices`) with their modern equivalents to ensure future compatibility. (#431)
 * Documentation added for all exported `*_data()` functions (#209)
diff --git a/R/helpers-ppc.R b/R/helpers-ppc.R
index e268b315..5206b9af 100644
--- a/R/helpers-ppc.R
+++ b/R/helpers-ppc.R
@@ -456,7 +456,7 @@ interpolate_gamma <- function(N, K, prob, L) {
 get_interpolation_values <- function(N, K, L, prob) {
   for (dim in c("L", "prob")) {
     if (all(get(dim) != .gamma_adj[, dim])) {
-      stop(paste(
+      abort(paste(
         "No precomputed values to interpolate from for '", dim, "' = ",
         get(dim),
         ".\n",
@@ -469,7 +469,7 @@ get_interpolation_values <- function(N, K, L, prob) {
   }
   vals <- .gamma_adj[.gamma_adj$L == L & .gamma_adj$prob == prob, ]
   if (N > max(vals$N)) {
-    stop(paste(
+    abort(paste(
       "No precomputed values to interpolate from for sample length of ",
       N,
       ".\n",
@@ -480,7 +480,7 @@ get_interpolation_values <- function(N, K, L, prob) {
     ))
   }
   if (N < min(vals$N)) {
-    stop(paste(
+    abort(paste(
       "No precomputed values to interpolate from for sample length of ",
       N,
       ".\n",
@@ -491,7 +491,7 @@ get_interpolation_values <- function(N, K, L, prob) {
     ))
   }
   if (K > max(vals[vals$N <= N, ]$K)) {
-    stop(paste(
+    abort(paste(
       "No precomputed values available for interpolation for 'K' = ",
       K,
       ".\n",
@@ -502,7 +502,7 @@ get_interpolation_values <- function(N, K, L, prob) {
     ))
   }
   if (K < min(vals[vals$N <= N, ]$K)) {
-    stop(paste(
+    abort(paste(
       "No precomputed values available for interpolation for 'K' = ",
       K,
       ".\n",
diff --git a/R/ppc-censoring.R b/R/ppc-censoring.R
index e41cbae9..d0588a90 100644
--- a/R/ppc-censoring.R
+++ b/R/ppc-censoring.R
@@ -113,17 +113,17 @@ ppc_km_overlay <- function(
   suggested_package("ggfortify")
 
   if (!is.numeric(status_y) || length(status_y) != length(y) || !all(status_y %in% c(0, 1))) {
-    stop("`status_y` must be a numeric vector of 0s and 1s the same length as `y`.", call. = FALSE)
+    abort("`status_y` must be a numeric vector of 0s and 1s the same length as `y`.")
   }
 
   if (!is.null(left_truncation_y)) {
     if (!is.numeric(left_truncation_y) || length(left_truncation_y) != length(y)) {
-      stop("`left_truncation_y` must be a numeric vector of the same length as `y`.", call. = FALSE)
+      abort("`left_truncation_y` must be a numeric vector of the same length as `y`.")
     }
   }
 
   if (extrapolation_factor < 1) {
-    stop("`extrapolation_factor` must be greater than or equal to 1.", call. = FALSE)
+    abort("`extrapolation_factor` must be greater than or equal to 1.")
   }
   if (extrapolation_factor == 1.2) {
     message(