diff --git a/goldens/trailing_commas.in b/goldens/trailing_commas.in
index ff51589..00dee8a 100644
--- a/goldens/trailing_commas.in
+++ b/goldens/trailing_commas.in
@@ -7,7 +7,6 @@ Trailing comma except for last
 
 
 Trailing comma and a comment
-TODO: https://github.com/google/keep-sorted/issues/33 - Fix this
   keep-sorted-test start
   3, # three
   1,
@@ -15,17 +14,30 @@ TODO: https://github.com/google/keep-sorted/issues/33 - Fix this
   keep-sorted-test end
 
 Trailing comma except for last, last has a comment
-TODO: https://github.com/google/keep-sorted/issues/33 - Fix this
   keep-sorted-test start
   3,
-  1,
-  2  # two
+  1, <!-- one -->
+  2  <!-- two -->
   keep-sorted-test end
 
 Trailing comma and a comment, last has a comment
-TODO: https://github.com/google/keep-sorted/issues/33 - Fix this
   keep-sorted-test start
-  3, # three
+  3, -- three
   1,
-  2  # two
+  2  -- two
+  keep-sorted-test end
+
+Trailing commas with inline comment
+  keep-sorted-test start
+  "c" /* c */,
+  "b",
+  "a" /* a */
+  keep-sorted-test end
+
+Trailing commas with quoted comment characters
+TODO: https://github.com/google/keep-sorted/issues/33 - Fix this
+  keep-sorted-test start
+  "c",
+  "b, //",
+  "a, #"
   keep-sorted-test end
diff --git a/goldens/trailing_commas.out b/goldens/trailing_commas.out
index 749e403..6db1901 100644
--- a/goldens/trailing_commas.out
+++ b/goldens/trailing_commas.out
@@ -7,25 +7,37 @@ Trailing comma except for last
 
 
 Trailing comma and a comment
-TODO: https://github.com/google/keep-sorted/issues/33 - Fix this
   keep-sorted-test start
   1,
-  2
-  3, # three
+  2,
+  3 # three
   keep-sorted-test end
 
 Trailing comma except for last, last has a comment
-TODO: https://github.com/google/keep-sorted/issues/33 - Fix this
   keep-sorted-test start
-  1,
-  2  # two,
+  1, <!-- one -->
+  2,  <!-- two -->
   3
   keep-sorted-test end
 
 Trailing comma and a comment, last has a comment
-TODO: https://github.com/google/keep-sorted/issues/33 - Fix this
   keep-sorted-test start
   1,
-  2  # two
-  3, # three
+  2,  -- two
+  3 -- three
+  keep-sorted-test end
+
+Trailing commas with inline comment
+  keep-sorted-test start
+  "a", /* a */
+  "b",
+  "c" /* c */
+  keep-sorted-test end
+
+Trailing commas with quoted comment characters
+TODO: https://github.com/google/keep-sorted/issues/33 - Fix this
+  keep-sorted-test start
+  "a, #"
+  "b, //",
+  "c",
   keep-sorted-test end
diff --git a/keepsorted/block.go b/keepsorted/block.go
index 9ff284b..730fb6b 100644
--- a/keepsorted/block.go
+++ b/keepsorted/block.go
@@ -16,6 +16,7 @@ package keepsorted
 
 import (
 	"fmt"
+	"regexp"
 	"slices"
 	"strings"
 
@@ -389,13 +390,23 @@ func handleTrailingComma(lgs []*lineGroup) (trimTrailingComma func([]*lineGroup)
 		}
 	}
 
-	if n := len(dataGroups); n > 1 && allHaveSuffix(dataGroups[0:n-1], ",") && !dataGroups[n-1].hasSuffix(",") {
-		dataGroups[n-1].append(",")
+	knownCommentMarkersList := knownCommentMarkers()
+	for i, marker := range knownCommentMarkersList {
+		// Some comment markers, such as "/*", include regex metacharacters.
+		knownCommentMarkersList[i] = regexp.QuoteMeta(marker)
+	}
+	knownCommentMarkersStr := strings.Join(knownCommentMarkersList, "|")
+
+	commaLineEnd := regexp.MustCompile(fmt.Sprintf(",(\\s*(%s).*)?$", knownCommentMarkersStr))
+	lineEnd := regexp.MustCompile(fmt.Sprintf("(\\s*(%s).*)?$", knownCommentMarkersStr))
+
+	if n := len(dataGroups); n > 1 && allMatchSuffix(dataGroups[0:n-1], commaLineEnd) && !dataGroups[n-1].matchesSuffix(commaLineEnd) {
+		dataGroups[n-1].replaceSuffix(lineEnd, ",$1")
 
 		return func(lgs []*lineGroup) {
 			for i := len(lgs) - 1; i >= 0; i-- {
 				if len(lgs[i].lines) > 0 {
-					lgs[i].trimSuffix(",")
+					lgs[i].replaceSuffix(commaLineEnd, "$1")
 					return
 				}
 			}
@@ -405,9 +416,9 @@ func handleTrailingComma(lgs []*lineGroup) (trimTrailingComma func([]*lineGroup)
 	return func([]*lineGroup) {}
 }
 
-func allHaveSuffix(lgs []*lineGroup, s string) bool {
+func allMatchSuffix(lgs []*lineGroup, suffix *regexp.Regexp) bool {
 	for _, lg := range lgs {
-		if !lg.hasSuffix(s) {
+		if !lg.matchesSuffix(suffix) {
 			return false
 		}
 	}
diff --git a/keepsorted/keep_sorted_test.go b/keepsorted/keep_sorted_test.go
index b90cd0b..1dbf752 100644
--- a/keepsorted/keep_sorted_test.go
+++ b/keepsorted/keep_sorted_test.go
@@ -1126,6 +1126,21 @@ func TestLineSorting(t *testing.T) {
 				"foo",
 			},
 		},
+		{
+			name: "TrailingCommas_WithComments",
+
+			in: []string{
+				"foo,",
+				"baz, /* baz */",
+				"bar // bar",
+			},
+
+			want: []string{
+				"bar, // bar",
+				"baz, /* baz */",
+				"foo",
+			},
+		},
 		{
 			name: "IgnorePrefixes",
 
diff --git a/keepsorted/line_group.go b/keepsorted/line_group.go
index a637de8..0cb6adb 100644
--- a/keepsorted/line_group.go
+++ b/keepsorted/line_group.go
@@ -119,7 +119,7 @@ func groupLines(lines []string, metadata blockMetadata) []*lineGroup {
 	// Returns another boolean indicating whether the group should be ending
 	// after that line if so.
 	shouldAddToRegexDelimitedGroup := func(l string) (addToGroup bool, finishGroupAfter bool) {
-        if metadata.opts.GroupStartRegex != nil {
+		if metadata.opts.GroupStartRegex != nil {
 			// For GroupStartRegex, all non-regex-matching lines should be
 			// part of the group including prior lines.
 			return !matchesAnyRegex(l, metadata.opts.GroupStartRegex), false
@@ -408,11 +408,20 @@ func (lg *lineGroup) hasSuffix(s string) bool {
 	return len(lg.lines) > 0 && strings.HasSuffix(lg.lines[len(lg.lines)-1], s)
 }
 
+func (lg *lineGroup) matchesSuffix(re *regexp.Regexp) bool {
+	return len(lg.lines) > 0 && re.MatchString(lg.lines[len(lg.lines)-1])
+}
+
 func (lg *lineGroup) trimSuffix(s string) {
 	lg.access = accessRecorder{}
 	lg.lines[len(lg.lines)-1] = strings.TrimSuffix(lg.lines[len(lg.lines)-1], s)
 }
 
+func (lg *lineGroup) replaceSuffix(re *regexp.Regexp, replacement string) {
+	lg.access = accessRecorder{}
+	lg.lines[len(lg.lines)-1] = re.ReplaceAllString(lg.lines[len(lg.lines)-1], replacement)
+}
+
 func (lg *lineGroup) commentOnly() bool {
 	lg.access.commentOnly = true
 	return len(lg.lines) == 0
diff --git a/keepsorted/options.go b/keepsorted/options.go
index 6b5c6fa..928a79f 100644
--- a/keepsorted/options.go
+++ b/keepsorted/options.go
@@ -312,9 +312,13 @@ func formatIntList(intVals []int) string {
 	return strings.Join(vals, ",")
 }
 
+func knownCommentMarkers() []string {
+	return []string{"//", "#", "/*", "--", ";", "<!--"}
+}
+
 func guessCommentMarker(startLine string) string {
 	startLine = strings.TrimSpace(startLine)
-	for _, marker := range []string{"//", "#", "/*", "--", ";", "<!--"} {
+	for _, marker := range knownCommentMarkers() {
 		if strings.HasPrefix(startLine, marker) {
 			return marker
 		}