diff --git a/command_run.go b/command_run.go
index 676a14c676..1e9649300f 100644
--- a/command_run.go
+++ b/command_run.go
@@ -214,6 +214,10 @@ func (cmd *Command) run(ctx context.Context, osArgs []string) (_ context.Context
 
 	for _, flag := range cmd.allFlags() {
 		isSet := flag.IsSet()
+		// Propagate the command's slice/map separator config before PostParse
+		// so that env-var values are split with the same separator as CLI
+		// values (see https://github.com/urfave/cli/issues/2262).
+		cmd.setMultiValueParsingConfig(flag)
 		if err := flag.PostParse(); err != nil {
 			return ctx, err
 		}
diff --git a/command_test.go b/command_test.go
index dafee0bee6..e0dfc2ad91 100644
--- a/command_test.go
+++ b/command_test.go
@@ -4590,6 +4590,28 @@ func TestCommandSliceFlagSeparator(t *testing.T) {
 	r.Equal([]string{"ff", "dd", "gg", "t,u"}, cmd.Value("foo"))
 }
 
+// TestCommandSliceFlagSeparatorFromEnvVar is a regression test for
+// https://github.com/urfave/cli/issues/2262.
+// SliceFlagSeparator must be respected when flag values come from env vars,
+// not only when they are supplied on the command line.
+func TestCommandSliceFlagSeparatorFromEnvVar(t *testing.T) {
+	t.Setenv("FOO", "ff;dd;gg")
+
+	cmd := &Command{
+		SliceFlagSeparator: ";",
+		Flags: []Flag{
+			&StringSliceFlag{
+				Name:    "foo",
+				Sources: EnvVars("FOO"),
+			},
+		},
+	}
+
+	r := require.New(t)
+	r.NoError(cmd.Run(buildTestContext(t), []string{"app"}))
+	r.Equal([]string{"ff", "dd", "gg"}, cmd.Value("foo"))
+}
+
 func TestCommandMapKeyValueFlagSeparator(t *testing.T) {
 	cmd := &Command{
 		MapFlagKeyValueSeparator: ":",