diff --git a/changelog_unreleased/css/13577.md b/changelog_unreleased/css/13577.md
new file mode 100644
index 000000000..e19fe8491
--- /dev/null
+++ b/changelog_unreleased/css/13577.md
@@ -0,0 +1,32 @@
+#### Fix formatting of long `:is`, `:where`, and `:not` selectors (#13577 by @j-f1)
+
+Pseudo-selectors like `:is`, `:where`, and `:not` that can take multiple selectors as arguments are now formatted like function calls are in other languages. Previously, no special significance was attached to the commas between their “arguments,” leading to confusing wrapping behavior. There are likely still improvements to be made here — please open an issue with some example code if you find something that doesn’t look as expected.
+
+<!-- prettier-ignore -->
+```css
+/* Input */
+:where(
+  label > input:valid,
+  label > textarea:not(:empty),
+  label > button[disabled]
+) ~ .errors > .error { display: none; }
+
+/* Prettier stable */
+:where(label > input:valid, label > textarea:not(:empty), label
+    > button[disabled])
+  ~ .errors
+  > .error {
+  display: none;
+}
+
+/* Prettier main */
+:where(
+    label > input:valid,
+    label > textarea:not(:empty),
+    label > button[disabled]
+  )
+  ~ .errors
+  > .error {
+  display: none;
+}
+```
diff --git a/src/language-css/printer-postcss.js b/src/language-css/printer-postcss.js
index 7b9a89af4..20165c5fa 100644
--- a/src/language-css/printer-postcss.js
+++ b/src/language-css/printer-postcss.js
@@ -461,7 +461,12 @@ function genericPrint(path, options, print) {
       return [
         maybeToLowerCase(node.value),
         isNonEmptyArray(node.nodes)
-          ? ["(", join(", ", path.map(print, "nodes")), ")"]
+          ? group([
+              "(",
+              indent([softline, join([",", line], path.map(print, "nodes"))]),
+              softline,
+              ")",
+            ])
           : "",
       ];
 
diff --git a/tests/format/css/indent/__snapshots__/jsfmt.spec.js.snap b/tests/format/css/indent/__snapshots__/jsfmt.spec.js.snap
index e7457a685..b00a54f5c 100644
--- a/tests/format/css/indent/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/format/css/indent/__snapshots__/jsfmt.spec.js.snap
@@ -42,7 +42,9 @@ a {
 
 =====================================output=====================================
 a {
-  ~ .Pagination-itemWrapper:not(.is-separator):not([data-priority^="#{$priority}"])
+  ~ .Pagination-itemWrapper:not(.is-separator):not(
+      [data-priority^="#{$priority}"]
+    )
     ~ .Pagination-itemWrapper.is-separator[data-priority^="#{$priority}"] {
     display: flex;
   }
diff --git a/tests/format/css/pseudo-call/__snapshots__/jsfmt.spec.js.snap b/tests/format/css/pseudo-call/__snapshots__/jsfmt.spec.js.snap
index 50ebc77cb..5a3dbabd4 100644
--- a/tests/format/css/pseudo-call/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/format/css/pseudo-call/__snapshots__/jsfmt.spec.js.snap
@@ -1,5 +1,86 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`is.css format 1`] = `
+====================================options=====================================
+parsers: ["css"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+:is(ol, ul, menu:unsupported) :is(ol, ul) {
+    color: green;
+}
+
+:is(ol, ul) :is(ol, ul) ol {
+    list-style-type: lower-greek;
+    color: chocolate;
+}
+
+:is(ol, ul, menu, dir) :is(ol, ul, menu, dir) :is(ul, menu, dir) {
+  list-style-type: square;
+}
+
+/* Level 0 */
+h1 {
+  font-size: 30px;
+}
+/* Level 1 */
+:is(section, article, aside, nav) h1 {
+  font-size: 25px;
+}
+/* Level 2 */
+:is(section, article, aside, nav) :is(section, article, aside, nav) h1 {
+  font-size: 20px;
+}
+/* Level 3 */
+:is(section, article, aside, nav)  :is(section, article, aside, nav)  :is(section, article, aside, nav)  h1 {
+  font-size: 15px;
+}
+
+some-element:is(::before, ::after) {
+  display: block;
+}
+
+=====================================output=====================================
+:is(ol, ul, menu:unsupported) :is(ol, ul) {
+  color: green;
+}
+
+:is(ol, ul) :is(ol, ul) ol {
+  list-style-type: lower-greek;
+  color: chocolate;
+}
+
+:is(ol, ul, menu, dir) :is(ol, ul, menu, dir) :is(ul, menu, dir) {
+  list-style-type: square;
+}
+
+/* Level 0 */
+h1 {
+  font-size: 30px;
+}
+/* Level 1 */
+:is(section, article, aside, nav) h1 {
+  font-size: 25px;
+}
+/* Level 2 */
+:is(section, article, aside, nav) :is(section, article, aside, nav) h1 {
+  font-size: 20px;
+}
+/* Level 3 */
+:is(section, article, aside, nav)
+  :is(section, article, aside, nav)
+  :is(section, article, aside, nav)
+  h1 {
+  font-size: 15px;
+}
+
+some-element:is(::before, ::after) {
+  display: block;
+}
+
+================================================================================
+`;
+
 exports[`pseudo_call.css format 1`] = `
 ====================================options=====================================
 parsers: ["css"]
@@ -15,3 +96,60 @@ div:not(:last-child) {
 
 ================================================================================
 `;
+
+exports[`where.css format 1`] = `
+====================================options=====================================
+parsers: ["css"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+:where(#p0:checked ~ #play:checked ~ #c1:checked, #p1:checked ~ #play:checked ~ #c2:checked, #p2:checked ~ #play:checked ~ #cO:checked) ~ #result >
+#c { display: block; }
+
+:where(ol, ul, menu:unsupported) :where(ol, ul) {
+    color: green;
+}
+
+:where(ol, ul) :where(ol, ul) ol {
+    list-style-type: lower-greek;
+    color: chocolate;
+}
+
+:is(section.is-styling, aside.is-styling, footer.is-styling) a {
+  color: red;
+}
+
+:where(section.where-styling, aside.where-styling, footer.where-styling) a {
+  color: orange;
+}
+
+=====================================output=====================================
+:where(
+    #p0:checked ~ #play:checked ~ #c1:checked,
+    #p1:checked ~ #play:checked ~ #c2:checked,
+    #p2:checked ~ #play:checked ~ #cO:checked
+  )
+  ~ #result
+  > #c {
+  display: block;
+}
+
+:where(ol, ul, menu:unsupported) :where(ol, ul) {
+  color: green;
+}
+
+:where(ol, ul) :where(ol, ul) ol {
+  list-style-type: lower-greek;
+  color: chocolate;
+}
+
+:is(section.is-styling, aside.is-styling, footer.is-styling) a {
+  color: red;
+}
+
+:where(section.where-styling, aside.where-styling, footer.where-styling) a {
+  color: orange;
+}
+
+================================================================================
+`;
diff --git a/tests/format/css/pseudo-call/is.css b/tests/format/css/pseudo-call/is.css
new file mode 100644
index 000000000..4b26a4aa1
--- /dev/null
+++ b/tests/format/css/pseudo-call/is.css
@@ -0,0 +1,33 @@
+:is(ol, ul, menu:unsupported) :is(ol, ul) {
+    color: green;
+}
+
+:is(ol, ul) :is(ol, ul) ol {
+    list-style-type: lower-greek;
+    color: chocolate;
+}
+
+:is(ol, ul, menu, dir) :is(ol, ul, menu, dir) :is(ul, menu, dir) {
+  list-style-type: square;
+}
+
+/* Level 0 */
+h1 {
+  font-size: 30px;
+}
+/* Level 1 */
+:is(section, article, aside, nav) h1 {
+  font-size: 25px;
+}
+/* Level 2 */
+:is(section, article, aside, nav) :is(section, article, aside, nav) h1 {
+  font-size: 20px;
+}
+/* Level 3 */
+:is(section, article, aside, nav)  :is(section, article, aside, nav)  :is(section, article, aside, nav)  h1 {
+  font-size: 15px;
+}
+
+some-element:is(::before, ::after) {
+  display: block;
+}
diff --git a/tests/format/css/pseudo-call/where.css b/tests/format/css/pseudo-call/where.css
new file mode 100644
index 000000000..a52b9af46
--- /dev/null
+++ b/tests/format/css/pseudo-call/where.css
@@ -0,0 +1,19 @@
+:where(#p0:checked ~ #play:checked ~ #c1:checked, #p1:checked ~ #play:checked ~ #c2:checked, #p2:checked ~ #play:checked ~ #cO:checked) ~ #result >
+#c { display: block; }
+
+:where(ol, ul, menu:unsupported) :where(ol, ul) {
+    color: green;
+}
+
+:where(ol, ul) :where(ol, ul) ol {
+    list-style-type: lower-greek;
+    color: chocolate;
+}
+
+:is(section.is-styling, aside.is-styling, footer.is-styling) a {
+  color: red;
+}
+
+:where(section.where-styling, aside.where-styling, footer.where-styling) a {
+  color: orange;
+}