diff --git a/cmd/linters/main.go b/cmd/linters/main.go
index 9c6fff9d628..f288339af12 100644
--- a/cmd/linters/main.go
+++ b/cmd/linters/main.go
@@ -23,6 +23,7 @@ import (
 	"github.com/github/gh-aw/pkg/linters/excessivefuncparams"
 	"github.com/github/gh-aw/pkg/linters/fileclosenotdeferred"
 	"github.com/github/gh-aw/pkg/linters/fprintlnsprintf"
+	"github.com/github/gh-aw/pkg/linters/jsonmarshalignoredeerror"
 	"github.com/github/gh-aw/pkg/linters/largefunc"
 	"github.com/github/gh-aw/pkg/linters/manualmutexunlock"
 	"github.com/github/gh-aw/pkg/linters/osexitinlibrary"
@@ -53,6 +54,7 @@ func main() {
 		regexpcompileinfunction.Analyzer,
 		ssljson.Analyzer,
 		strconvparseignorederror.Analyzer,
+		jsonmarshalignoredeerror.Analyzer,
 		uncheckedtypeassertion.Analyzer,
 	)
 }
diff --git a/pkg/linters/jsonmarshalignoredeerror/jsonmarshalignoredeerror.go b/pkg/linters/jsonmarshalignoredeerror/jsonmarshalignoredeerror.go
new file mode 100644
index 00000000000..7ae82078b13
--- /dev/null
+++ b/pkg/linters/jsonmarshalignoredeerror/jsonmarshalignoredeerror.go
@@ -0,0 +1,79 @@
+// Package jsonmarshalignoredeerror implements a Go analysis linter that flags
+// json.Marshal and json.Unmarshal calls where the error return is discarded with _.
+package jsonmarshalignoredeerror
+
+import (
+	"go/ast"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+)
+
+// Analyzer is the json-marshal-ignored-error analysis pass.
+var Analyzer = &analysis.Analyzer{
+	Name:     "jsonmarshalignoredeerror",
+	Doc:      "reports json.Marshal and json.Unmarshal calls where the error return is discarded with _",
+	URL:      "https://github.com/github/gh-aw/tree/main/pkg/linters/jsonmarshalignoredeerror",
+	Requires: []*analysis.Analyzer{inspect.Analyzer},
+	Run:      run,
+}
+
+func run(pass *analysis.Pass) (any, error) {
+	insp := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+	nodeFilter := []ast.Node{(*ast.AssignStmt)(nil)}
+	insp.Preorder(nodeFilter, func(n ast.Node) {
+		assign, ok := n.(*ast.AssignStmt)
+		if !ok {
+			return
+		}
+
+		// Pattern: val, _ := json.Marshal(x)  — 2 lhs, 1 rhs, Lhs[1] is blank
+		if len(assign.Lhs) == 2 && len(assign.Rhs) == 1 {
+			blank, ok := assign.Lhs[1].(*ast.Ident)
+			if ok && blank.Name == "_" {
+				call, ok := assign.Rhs[0].(*ast.CallExpr)
+				if ok {
+					if isJSONFunc(pass, call, "Marshal") {
+						pass.ReportRangef(call, "error return from json.Marshal is discarded; marshal failures produce nil bytes silently")
+					}
+				}
+			}
+		}
+
+		// Pattern: _ = json.Unmarshal(data, &v)  — 1 lhs, 1 rhs, Lhs[0] is blank
+		if len(assign.Lhs) == 1 && len(assign.Rhs) == 1 {
+			blank, ok := assign.Lhs[0].(*ast.Ident)
+			if ok && blank.Name == "_" {
+				call, ok := assign.Rhs[0].(*ast.CallExpr)
+				if ok {
+					if isJSONFunc(pass, call, "Unmarshal") {
+						pass.ReportRangef(call, "error return from json.Unmarshal is discarded; unmarshal failures leave the target value in a partial state")
+					}
+				}
+			}
+		}
+	})
+	return nil, nil
+}
+
+func isJSONFunc(pass *analysis.Pass, call *ast.CallExpr, name string) bool {
+	sel, ok := call.Fun.(*ast.SelectorExpr)
+	if !ok {
+		return false
+	}
+	if sel.Sel.Name != name {
+		return false
+	}
+	ident, ok := sel.X.(*ast.Ident)
+	if !ok {
+		return false
+	}
+	obj := pass.TypesInfo.Uses[ident]
+	pkgName, ok := obj.(*types.PkgName)
+	if !ok {
+		return false
+	}
+	return pkgName.Imported().Path() == "encoding/json"
+}
diff --git a/pkg/linters/jsonmarshalignoredeerror/jsonmarshalignoredeerror_test.go b/pkg/linters/jsonmarshalignoredeerror/jsonmarshalignoredeerror_test.go
new file mode 100644
index 00000000000..03aca55b769
--- /dev/null
+++ b/pkg/linters/jsonmarshalignoredeerror/jsonmarshalignoredeerror_test.go
@@ -0,0 +1,16 @@
+//go:build !integration
+
+package jsonmarshalignoredeerror_test
+
+import (
+	"testing"
+
+	"golang.org/x/tools/go/analysis/analysistest"
+
+	"github.com/github/gh-aw/pkg/linters/jsonmarshalignoredeerror"
+)
+
+func TestAnalyzer(t *testing.T) {
+	testdata := analysistest.TestData()
+	analysistest.Run(t, testdata, jsonmarshalignoredeerror.Analyzer, "jsonmarshalignoredeerror")
+}
diff --git a/pkg/linters/jsonmarshalignoredeerror/testdata/src/jsonmarshalignoredeerror/jsonmarshalignoredeerror.go b/pkg/linters/jsonmarshalignoredeerror/testdata/src/jsonmarshalignoredeerror/jsonmarshalignoredeerror.go
new file mode 100644
index 00000000000..0d8532b5da4
--- /dev/null
+++ b/pkg/linters/jsonmarshalignoredeerror/testdata/src/jsonmarshalignoredeerror/jsonmarshalignoredeerror.go
@@ -0,0 +1,29 @@
+package jsonmarshalignoredeerror
+
+import "encoding/json"
+
+type Foo struct{ X int }
+
+func Bad() {
+	f := Foo{X: 1}
+	val, _ := json.Marshal(f) // want `error return from json\.Marshal is discarded`
+	_ = val
+
+	var f2 Foo
+	_ = json.Unmarshal([]byte(`{}`), &f2) // want `error return from json\.Unmarshal is discarded`
+}
+
+func Good() error {
+	f := Foo{X: 1}
+	val, err := json.Marshal(f)
+	if err != nil {
+		return err
+	}
+	_ = val
+
+	var f2 Foo
+	if err := json.Unmarshal([]byte(`{}`), &f2); err != nil {
+		return err
+	}
+	return nil
+}