diff --git a/Project.toml b/Project.toml
index 9488594d3..268b3a323 100644
--- a/Project.toml
+++ b/Project.toml
@@ -5,6 +5,7 @@ version = "0.9.17"
 
 [deps]
 Base64 = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
+CodecZlib = "944b1d66-785c-5afd-91f1-9de20f533193"
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
 IniFile = "83e8ac13-25f8-5344-8a64-a9f2b223428f"
 Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
@@ -15,8 +16,8 @@ Sockets = "6462fe0b-24de-5631-8697-dd941f90decc"
 URIs = "5c2747f8-b7ea-4ff2-ba2e-563bfd36b1d4"
 
 [compat]
-LoggingExtras = "0.5"
 IniFile = "0.5"
+LoggingExtras = "0.5"
 MbedTLS = "0.6.8, 0.7, 1"
 URIs = "1.3"
 julia = "1.6"
diff --git a/src/DebugRequest.jl b/src/DebugRequest.jl
index 28a8b77c3..1685867d7 100644
--- a/src/DebugRequest.jl
+++ b/src/DebugRequest.jl
@@ -12,9 +12,9 @@ If `verbose` keyword arg is > 0, or the HTTP.jl global `DEBUG_LEVEL[]` is > 0,
 then enabled debug logging with verbosity `verbose` for the lifetime of the request.
 """
 function debuglayer(handler)
-    return function(request; verbose::Int=0, kw...)
+    return function(request; verbose=0, kw...)
         # if debugging, enable by wrapping request in custom logger logic
-        if verbose >= 0 || DEBUG_LEVEL[] >= 0
+        if verbose > 0 || DEBUG_LEVEL[] > 0
             LoggingExtras.withlevel(Logging.Debug; verbosity=verbose) do
                 handler(request; verbose=verbose, kw...)
             end
diff --git a/src/HTTP.jl b/src/HTTP.jl
index 9e5bdcb66..9742d70ff 100644
--- a/src/HTTP.jl
+++ b/src/HTTP.jl
@@ -29,7 +29,7 @@ include("access_log.jl")
 
 include("Pairs.jl")                    ;using .Pairs
 include("IOExtras.jl")                 ;using .IOExtras
-include("Strings.jl")
+include("Strings.jl")                  ;using .Strings
 include("sniff.jl")
 include("multipart.jl")
 include("Parsers.jl")                  ;import .Parsers: Headers, Header,
diff --git a/src/Messages.jl b/src/Messages.jl
index 0abdb116e..f6d28071b 100644
--- a/src/Messages.jl
+++ b/src/Messages.jl
@@ -62,11 +62,12 @@ export Message, Request, Response,
        readchunksize,
        writeheaders, writestartline,
        bodylength, unknown_length,
-       payload, statustext
+       payload, decode, statustext
 
 import ..HTTP
 
 using ..URIs
+using CodecZlib
 using ..Pairs
 using ..IOExtras
 using ..Parsers
@@ -483,9 +484,8 @@ payload(m::Message, ::Type{String}) =
 
 function decode(m::Message, encoding::String)::Vector{UInt8}
     if encoding == "gzip"
-        # Use https://github.com/bicycle1885/TranscodingStreams.jl ?
+        return transcode(GzipDecompressor, m.body)
     end
-    @warn "Decoding of HTTP Transfer-Encoding is not implemented yet!"
     return m.body
 end
 
diff --git a/src/Parsers.jl b/src/Parsers.jl
index 73527089b..5ae00ff8b 100644
--- a/src/Parsers.jl
+++ b/src/Parsers.jl
@@ -17,7 +17,7 @@ have field names compatible with those expected by the `parse_status_line!` and
 """
 module Parsers
 
-import ..access_threaded
+import ..access_threaded, ..iso8859_1_to_utf8
 
 export Header, Headers,
        find_end_of_header, find_end_of_chunk_size, find_end_of_trailer,
@@ -222,19 +222,7 @@ function parse_header_field(bytes::SubString{String})::Tuple{Header,SubString{St
     # these from latin-1 => utf-8 and then try to parse.
     if !isvalid(bytes)
         @warn "malformed HTTP header detected; attempting to re-encode from Latin-1 to UTF8"
-        rawbytes = codeunits(bytes)
-        buf = Base.StringVector(length(rawbytes) + count(≥(0x80), rawbytes))
-        i = 0
-        for byte in rawbytes
-            if byte ≥ 0x80
-                buf[i += 1] = 0xc0 | (byte >> 6)
-                buf[i += 1] = 0x80 | (byte & 0x3f)
-            else
-                buf[i += 1] = byte
-            end
-        end
-        bytes = SubString(String(buf))
-        !isvalid(bytes) && @goto error
+        bytes = SubString(iso8859_1_to_utf8(codeunits(bytes)))
     end
 
     # First look for: field-name ":" field-value
diff --git a/src/StreamRequest.jl b/src/StreamRequest.jl
index 29aef0fb1..bad991172 100644
--- a/src/StreamRequest.jl
+++ b/src/StreamRequest.jl
@@ -7,7 +7,7 @@ import ..ConnectionPool
 using ..MessageRequest
 import ..RedirectRequest: nredirects
 import ..sprintcompact
-using LoggingExtras
+using LoggingExtras, CodecZlib
 
 export streamlayer
 
@@ -22,7 +22,7 @@ immediately so that the transmission can be aborted if the `Response` status
 indicates that the server does not wish to receive the message body.
 [RFC7230 6.5](https://tools.ietf.org/html/rfc7230#section-6.5).
 """
-function streamlayer(stream::Stream; iofunction=nothing, redirect_limit::Int=3, kw...)::Response
+function streamlayer(stream::Stream; iofunction=nothing, redirect_limit::Int=3, decompress::Bool=true, kw...)::Response
     response = stream.message
     req = response.request
     io = stream.stream
@@ -49,7 +49,7 @@ function streamlayer(stream::Stream; iofunction=nothing, redirect_limit::Int=3,
                 end
                 @debugv 2 "client startread"
                 startread(stream)
-                readbody(stream, response, redirect_limit == nredirects(req))
+                readbody(stream, response, redirect_limit == nredirects(req), decompress)
             else
                 iofunction(stream)
             end
@@ -103,7 +103,10 @@ end
 writechunk(stream, body::IO) = writebodystream(stream, body)
 writechunk(stream, body) = write(stream, body)
 
-function readbody(stream::Stream, res::Response, redirectlimitreached)
+function readbody(stream::Stream, res::Response, redirectlimitreached, decompress)
+    if decompress && header(res, "Content-Encoding") == "gzip"
+        stream = GzipDecompressorStream(stream)
+    end
     if isbytes(res.body)
         res.body = read(stream)
     else
diff --git a/src/Strings.jl b/src/Strings.jl
index 3d841e647..4f7b128c8 100644
--- a/src/Strings.jl
+++ b/src/Strings.jl
@@ -54,14 +54,14 @@ tocameldash(s::AbstractString) = tocameldash(String(s))
 
 Convert from ISO8859_1 to UTF8.
 """
-function iso8859_1_to_utf8(bytes::Vector{UInt8})
+function iso8859_1_to_utf8(bytes::AbstractVector{UInt8})
     io = IOBuffer()
     for b in bytes
         if b < 0x80
             write(io, b)
         else
-            write(io, 0xc0 | b >> 6)
-            write(io, 0x80 | b & 0x3f)
+            write(io, 0xc0 | (b >> 6))
+            write(io, 0x80 | (b & 0x3f))
         end
     end
     return String(take!(io))
diff --git a/test/client.jl b/test/client.jl
index 59f460310..21285004f 100644
--- a/test/client.jl
+++ b/test/client.jl
@@ -29,6 +29,17 @@ end
         @test status(HTTP.patch("$sch://httpbin.org/patch")) == 200
     end
 
+    @testset "decompress" begin
+        r = HTTP.get("$sch://httpbin.org/gzip")
+        @test status(r) == 200
+        @test isascii(String(r.body))
+        r = HTTP.get("$sch://httpbin.org/gzip"; decompress=false)
+        @test status(r) == 200
+        @test !isascii(String(r.body))
+        r = HTTP.get("$sch://httpbin.org/gzip"; decompress=false)
+        @test isascii(String(HTTP.decode(r, "gzip")))
+    end
+
     @testset "ASync Client Requests" begin
         @test status(fetch(@async HTTP.get("$sch://httpbin.org/ip"))) == 200
         @test status(HTTP.get("$sch://httpbin.org/encoding/utf8")) == 200