diff --git a/environment.go b/environment.go
index dd493d7e2..9f2dc9dd4 100644
--- a/environment.go
+++ b/environment.go
@@ -2,6 +2,7 @@ package httpexpect
 
 import (
 	"errors"
+	"sync"
 	"time"
 )
 
@@ -13,9 +14,9 @@ import (
 //	env.Put("key", "value")
 //	value := env.GetString("key")
 type Environment struct {
-	noCopy noCopy
-	chain  *chain
-	data   map[string]interface{}
+	mu    sync.RWMutex
+	chain *chain
+	data  map[string]interface{}
 }
 
 // NewEnvironment returns a new Environment.
@@ -58,6 +59,9 @@ func (e *Environment) Put(key string, value interface{}) {
 	opChain := e.chain.enter("Put(%q)", key)
 	defer opChain.leave()
 
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
 	e.data[key] = value
 }
 
@@ -72,6 +76,9 @@ func (e *Environment) Delete(key string) {
 	opChain := e.chain.enter("Delete(%q)", key)
 	defer opChain.leave()
 
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
 	delete(e.data, key)
 }
 
@@ -86,6 +93,9 @@ func (e *Environment) Has(key string) bool {
 	opChain := e.chain.enter("Has(%q)", key)
 	defer opChain.leave()
 
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+
 	_, ok := e.data[key]
 	return ok
 }
@@ -102,6 +112,9 @@ func (e *Environment) Get(key string) interface{} {
 	opChain := e.chain.enter("Get(%q)", key)
 	defer opChain.leave()
 
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+
 	value, _ := envValue(opChain, e.data, key)
 
 	return value
@@ -118,6 +131,9 @@ func (e *Environment) GetBool(key string) bool {
 	opChain := e.chain.enter("GetBool(%q)", key)
 	defer opChain.leave()
 
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+
 	value, ok := envValue(opChain, e.data, key)
 	if !ok {
 		return false
@@ -150,6 +166,9 @@ func (e *Environment) GetInt(key string) int {
 	opChain := e.chain.enter("GetInt(%q)", key)
 	defer opChain.leave()
 
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+
 	value, ok := envValue(opChain, e.data, key)
 	if !ok {
 		return 0
@@ -235,6 +254,9 @@ func (e *Environment) GetFloat(key string) float64 {
 	opChain := e.chain.enter("GetFloat(%q)", key)
 	defer opChain.leave()
 
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+
 	value, ok := envValue(opChain, e.data, key)
 	if !ok {
 		return 0
@@ -275,6 +297,9 @@ func (e *Environment) GetString(key string) string {
 	opChain := e.chain.enter("GetString(%q)", key)
 	defer opChain.leave()
 
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+
 	value, ok := envValue(opChain, e.data, key)
 	if !ok {
 		return ""
@@ -306,6 +331,9 @@ func (e *Environment) GetBytes(key string) []byte {
 	opChain := e.chain.enter("GetBytes(%q)", key)
 	defer opChain.leave()
 
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+
 	value, ok := envValue(opChain, e.data, key)
 	if !ok {
 		return nil
@@ -338,6 +366,9 @@ func (e *Environment) GetDuration(key string) time.Duration {
 	opChain := e.chain.enter("GetDuration(%q)", key)
 	defer opChain.leave()
 
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+
 	value, ok := envValue(opChain, e.data, key)
 	if !ok {
 		return time.Duration(0)
@@ -370,6 +401,9 @@ func (e *Environment) GetTime(key string) time.Time {
 	opChain := e.chain.enter("GetTime(%q)", key)
 	defer opChain.leave()
 
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+
 	value, ok := envValue(opChain, e.data, key)
 	if !ok {
 		return time.Unix(0, 0)
diff --git a/environment_test.go b/environment_test.go
index 02d78856b..dfe698b2e 100644
--- a/environment_test.go
+++ b/environment_test.go
@@ -32,6 +32,23 @@ func TestEnvironment_Constructors(t *testing.T) {
 	})
 }
 
+func TestEnvironment_Reentrant(t *testing.T) {
+	reporter := newMockReporter(t)
+
+	env := NewEnvironment(reporter)
+
+	reportCalled := false
+	reporter.reportCb = func() {
+		env.Put("good_key", 123)
+		reportCalled = true
+	}
+
+	env.Get("bad_key")
+	env.chain.assertFailed(t)
+
+	assert.True(t, reportCalled)
+}
+
 func TestEnvironment_Basic(t *testing.T) {
 	env := newEnvironment(newMockChain(t))
 
diff --git a/mocks_test.go b/mocks_test.go
index 6b14084cf..316c8f2c9 100644
--- a/mocks_test.go
+++ b/mocks_test.go
@@ -183,6 +183,7 @@ func (l *mockLogger) Logf(message string, args ...interface{}) {
 type mockReporter struct {
 	testing  *testing.T
 	reported bool
+	reportCb func()
 }
 
 func newMockReporter(t *testing.T) *mockReporter {
@@ -192,6 +193,10 @@ func newMockReporter(t *testing.T) *mockReporter {
 func (r *mockReporter) Errorf(message string, args ...interface{}) {
 	r.testing.Logf("Fail: "+message, args...)
 	r.reported = true
+
+	if r.reportCb != nil {
+		r.reportCb()
+	}
 }
 
 type mockFormatter struct {