diff --git a/.changeset/fix-tom-select-validation-colors.md b/.changeset/fix-tom-select-validation-colors.md
new file mode 100644
index 000000000..330130642
--- /dev/null
+++ b/.changeset/fix-tom-select-validation-colors.md
@@ -0,0 +1,5 @@
+---
+"@tabler/core": patch
+---
+
+Fixed `.is-valid` and `.is-invalid` border colors and focus ring on Tom Select `.form-select` fields.
diff --git a/core/scss/tests/__snapshots__/css-var-prefix.test.mjs.snap b/core/scss/tests/__snapshots__/css-var-prefix.test.mjs.snap
index 4db8246f3..42ad5af96 100644
--- a/core/scss/tests/__snapshots__/css-var-prefix.test.mjs.snap
+++ b/core/scss/tests/__snapshots__/css-var-prefix.test.mjs.snap
@@ -56,13 +56,16 @@ exports[`css custom-property prefixing > leaves vendor-owned names alone and pre
   "--tblr-chart-3",
   "--tblr-chart-4",
   "--tblr-chart-5",
+  "--tblr-danger",
   "--tblr-font-sans-serif",
   "--tblr-font-size-h3",
   "--tblr-font-size-h5",
   "--tblr-font-weight-medium",
   "--tblr-font-weight-semibold",
+  "--tblr-form-invalid-border-color",
   "--tblr-form-select-bg-icon",
   "--tblr-form-select-bg-img",
+  "--tblr-form-valid-border-color",
   "--tblr-gray-500",
   "--tblr-green",
   "--tblr-icon-size",
@@ -78,6 +81,7 @@ exports[`css custom-property prefixing > leaves vendor-owned names alone and pre
   "--tblr-shadow-card",
   "--tblr-shadow-dropdown",
   "--tblr-shadow-input",
+  "--tblr-success",
   "--tblr-tertiary",
   "--tblr-text-inverted",
   "--tblr-yellow",
diff --git a/core/scss/vendor/_tom-select.scss b/core/scss/vendor/_tom-select.scss
index 33489e177..632e0e2fa 100644
--- a/core/scss/vendor/_tom-select.scss
+++ b/core/scss/vendor/_tom-select.scss
@@ -1,3 +1,4 @@
+@use 'sass:map';
 @use '../config' as *;
 
 $input-border-width: 1px;
@@ -52,6 +53,23 @@ $input-border-width: 1px;
       background-image: var(--form-select-bg-img), var(--form-select-bg-icon, none);
     }
   }
+
+  // The same preset also colours the wrapper border and the focused
+  // `.ts-control` with `var(--bs-form-valid-color)` / `--bs-form-invalid-color`.
+  // Those variables do not exist in Tabler, so the border falls back to
+  // `currentColor` and the focus ring disappears. Repeat Tabler's own
+  // validation colours; `!important` for the same reason as `.ts-dropdown`
+  // below.
+  @each $state, $data in $form-validation-states {
+    &.is-#{$state} {
+      border-color: map.get($data, 'border-color') !important;
+
+      &.focus .ts-control {
+        border-color: map.get($data, 'border-color') !important;
+        box-shadow: map.get($data, 'focus-box-shadow') !important;
+      }
+    }
+  }
 }
 
 // The bootstrap5 preset hardcodes Bootstrap's own input metrics on