diff --git a/README.md b/README.md
index f9fee9e..e1b6c94 100644
--- a/README.md
+++ b/README.md
@@ -390,8 +390,9 @@ The `REQUEST` object contains a parsed and normalized request from API Gateway.
 - `path`: The path passed in by the request including the `base` and any `prefix` assigned to routes
 - `query`: Querystring parameters parsed into an object
 - `multiValueQuery`: Querystring parameters with multiple values parsed into an object with array values
-- `headers`: An object containing the request headers (properties converted to lowercase for HTTP/2, see [rfc7540 8.1.2. HTTP Header Fields](https://tools.ietf.org/html/rfc7540))
+- `headers`: An object containing the request headers (properties converted to lowercase for HTTP/2, see [rfc7540 8.1.2. HTTP Header Fields](https://tools.ietf.org/html/rfc7540)). Note that multi-value headers are concatenated with a comma per [rfc2616 4.2. Message Headers](https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2).
 - `rawHeaders`: An object containing the original request headers (property case preserved)
+- `multiValueHeaders`: An object containing header values as multi-value arrays
 - `body`: The body of the request. If the `isBase64Encoded` flag is `true`, it will be decoded automatically.
   - If the `content-type` header is `application/json`, it will attempt to parse the request using `JSON.parse()`
   - If the `content-type` header is `application/x-www-form-urlencoded`, it will attempt to parse a URL encoded string using `querystring`
diff --git a/lib/request.js b/lib/request.js
index 44511d9..da51246 100644
--- a/lib/request.js
+++ b/lib/request.js
@@ -82,15 +82,21 @@ class REQUEST {
         .reduce((qs,key) => Object.assign(qs, { [key]: [this.query[key]] }), {}),
       this.app._event.multiValueQueryStringParameters)
 
-    // Set the raw headers
-    this.rawHeaders = this.app._event.headers || {}
-    // this.rawHeaders = this._multiValueSupport ? this.app._event.multiValueHeaders
-    //   : this.app._event.headers
+    // Set the raw headers (normalize multi-values)
+    // per https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
+    this.rawHeaders = this._multiValueSupport ?
+      Object.keys(this.app._event.multiValueHeaders).reduce((headers,key) =>
+        Object.assign(headers,{ [key]: UTILS.fromArray(this.app._event.multiValueHeaders[key]) }),{})
+        : this.app._event.headers || {}
 
     // Set the headers to lowercase
     this.headers = Object.keys(this.rawHeaders).reduce((acc,header) =>
       Object.assign(acc,{[header.toLowerCase()]:this.rawHeaders[header]}), {})
 
+    this.multiValueHeaders = this._multiValueSupport ? this.app._event.multiValueHeaders
+      : Object.keys(this.headers).reduce((headers,key) =>
+          Object.assign(headers,{ [key.toLowerCase()]: [this.headers[key]] }),{})
+
     // Extract user agent
     this.userAgent = this.headers['user-agent']
 
diff --git a/lib/utils.js b/lib/utils.js
index 7bd4270..8071760 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -134,3 +134,7 @@ exports.deepMerge = (a,b) => {
     this.deepMerge(a[key],b[key]) : Object.assign(a,b) )
   return a
 }
+
+// Concats values from an array to ',' separated string
+exports.fromArray = val =>
+  val && val instanceof Array ? val.toString() : undefined
diff --git a/test/requests.js b/test/requests.js
index b3619e2..357b8a6 100644
--- a/test/requests.js
+++ b/test/requests.js
@@ -29,6 +29,7 @@ describe('Request Tests:', function() {
       let result = await new Promise(r => api.run(_event,_context,(e,res) => { r(res) }))
       let body = JSON.parse(result.body)
       // console.log(body);
+      // console.log(body.request.multiValueHeaders);
       expect(result.headers).to.deep.equal({ 'content-type': 'application/json' })
       expect(body).to.have.property('request')
       expect(body.request.id).is.not.null
@@ -46,12 +47,15 @@ describe('Request Tests:', function() {
       expect(body.request.query.qs2).to.equal('bar')
       expect(body.request.multiValueQuery.qs2).to.deep.equal(['foo','bar'])
       expect(body.request.multiValueQuery.qs3).to.deep.equal(['bat','baz'])
+      expect(body.request.headers['test-header']).to.equal('val1,val2')
+      expect(body.request.multiValueHeaders['test-header']).to.deep.equal(['val1','val2'])
     })
 
     it('Missing X-Forwarded-For (sourceIp fallback)', async function() {
       let _event = require('./sample-event-apigateway1.json')
       let _context = require('./sample-context-apigateway1.json')
       delete _event.headers['X-Forwarded-For'] // remove the header
+      delete _event.multiValueHeaders['x-forwarded-for'] // remove the header
       let result = await new Promise(r => api.run(_event,_context,(e,res) => { r(res) }))
       let body = JSON.parse(result.body)
       expect(result.headers).to.deep.equal({ 'content-type': 'application/json' })
@@ -71,6 +75,8 @@ describe('Request Tests:', function() {
       expect(body.request.query.qs2).to.equal('bar')
       expect(body.request.multiValueQuery.qs2).to.deep.equal(['foo','bar'])
       expect(body.request.multiValueQuery.qs3).to.deep.equal(['bat','baz'])
+      expect(body.request.headers['test-header']).to.equal('val1,val2')
+      expect(body.request.multiValueHeaders['test-header']).to.deep.equal(['val1','val2'])
       // console.log(body);
     })
   })
@@ -94,12 +100,40 @@ describe('Request Tests:', function() {
       expect(body.request.clientCountry).to.equal('unknown')
       expect(body.request.route).to.equal('/test/hello')
       expect(body.request.query.qs1).to.equal('foo')
+      expect(body.request.multiValueQuery.qs1).to.deep.equal(['foo'])
+      console.log(body.request.multiValueHeaders)
       // expect(body.request.query.qs2).to.equal('bar')
       // expect(body.request.multiValueQuery.qs2).to.deep.equal(['foo','bar'])
       // expect(body.request.multiValueQuery.qs3).to.deep.equal(['bat','baz'])
 
     })
 
+
+    it('With multi-value support', async function() {
+      let _event = require('./sample-event-alb2.json')
+      let _context = require('./sample-context-alb1.json')
+      let result = await new Promise(r => api.run(_event,_context,(e,res) => { r(res) }))
+      let body = JSON.parse(result.body)
+      // console.log(body);
+      expect(result.headers).to.deep.equal({ 'content-type': 'application/json' })
+      expect(body).to.have.property('request')
+      expect(body.request.id).is.not.null
+      expect(body.request.interface).to.equal('alb')
+      expect(body.request.userAgent).to.equal('Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.82 Safari/537.36 OPR/39.0.2256.48')
+      expect(body.request).to.have.property('requestContext')
+      expect(body.request.ip).to.equal('192.168.100.1')
+      expect(body.request.isBase64Encoded).to.equal(true)
+      expect(body.request.clientType).to.equal('unknown')
+      expect(body.request.clientCountry).to.equal('unknown')
+      expect(body.request.route).to.equal('/test/hello')
+      expect(body.request.query.qs1).to.equal('foo')
+      expect(body.request.multiValueQuery.qs1).to.deep.equal(['foo'])
+      expect(body.request.multiValueQuery.qs2).to.deep.equal(['foo','bar'])
+      expect(body.request.multiValueQuery.qs3).to.deep.equal(['foo','bar','bat'])
+      expect(body.request.headers['test-header']).to.equal('val1,val2')
+      expect(body.request.multiValueHeaders['test-header']).to.deep.equal(['val1','val2'])
+    })
+
   })
 
 }) // end Request tests
diff --git a/test/sample-event-alb2.json b/test/sample-event-alb2.json
new file mode 100644
index 0000000..5ac3384
--- /dev/null
+++ b/test/sample-event-alb2.json
@@ -0,0 +1,29 @@
+{
+  "requestContext": {
+    "elb": {
+      "targetGroupArn": "arn:aws:elasticloadbalancing:us-east-1:XXXXXXXXXX:targetgroup/Test-ALB-Lambda/XXXXXXX"
+    }
+  },
+  "httpMethod": "GET",
+  "path": "/test/hello",
+  "multiValueQueryStringParameters": {
+    "qs1": [ "foo" ],
+    "qs2": [ "foo", "bar" ],
+    "qs3": [ "foo", "bar", "bat" ]
+  },
+  "multiValueHeaders": {
+    "accept": ["text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"],
+    "accept-encoding": ["br, gzip, deflate"],
+    "accept-language": ["en-us"],
+    "cookie": [""],
+    "host": ["wt6mne2s9k.execute-api.us-west-2.amazonaws.com"],
+    "user-agent": ["Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.82 Safari/537.36 OPR/39.0.2256.48"],
+    "x-amzn-trace-id": ["Root=1-5c1db69f-XXXXXXXXXXX"],
+    "x-forwarded-for": ["192.168.100.1"],
+    "x-forwarded-port": ["443"],
+    "x-forwarded-proto": ["https"],
+    "test-header": ["val1","val2"]
+  },
+  "body": "",
+  "isBase64Encoded": true
+}
diff --git a/test/sample-event-apigateway1.json b/test/sample-event-apigateway1.json
index cad04ef..bafa651 100644
--- a/test/sample-event-apigateway1.json
+++ b/test/sample-event-apigateway1.json
@@ -19,6 +19,26 @@
     "X-Forwarded-Port": "443",
     "X-Forwarded-Proto": "https"
   },
+  "multiValueHeaders": {
+    "accept": ["text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8"],
+    "accept-encoding": ["gzip, deflate, lzma, sdch, br"],
+    "accept-language": ["en-US,en;q=0.8"],
+    "cloudfront-forwarded-proto": ["https"],
+    "cloudfront-is-desktop-viewer": ["true"],
+    "cloudfront-is-mobile-viewer": ["false"],
+    "cloudfront-is-smarttv-viewer": ["false"],
+    "cloudfront-is-tablet-viewer": ["false"],
+    "cloudfront-viewer-country": ["US"],
+    "host": ["wt6mne2s9k.execute-api.us-west-2.amazonaws.com"],
+    "upgrade-insecure-requests": ["1"],
+    "user-agent": ["Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.82 Safari/537.36 OPR/39.0.2256.48"],
+    "via": ["1.1 fb7cca60f0ecd82ce07790c9c5eef16c.cloudfront.net (CloudFront)"],
+    "x-amz-cf-id": ["nBsWBOrSHMgnaROZJK1wGCZ9PcRcSpq_oSXZNQwQ10OTZL4cimZo3g=="],
+    "x-forwarded-for": ["192.168.100.1, 192.168.1.1"],
+    "x-forwarded-port": ["443"],
+    "x-forwarded-proto": ["https"],
+    "test-header": ["val1","val2"]
+  },
   "pathParameters": {
     "proxy": "hello"
   },
@@ -52,7 +72,7 @@
   },
   "multiValueQueryStringParameters": {
     "qs2": [ "foo", "bar" ],
-    "qs3": [ "bat", "baz" ] 
+    "qs3": [ "bat", "baz" ]
   },
   "stageVariables": {
     "stageVarName": "stageVarValue"