diff --git a/Makefile b/Makefile
index 3ecfa730d..af128130d 100644
--- a/Makefile
+++ b/Makefile
@@ -81,6 +81,9 @@ fix-indent:
 build-deps:
 	@./scripts/install_build_deps.sh
 
+build-dev-deps:
+	@./scripts/install_build_deps.sh --dev
+
 docker-image:
 	@./scripts/create_docker_image.sh
 
diff --git a/docs/introduction/howtoget.rst b/docs/introduction/howtoget.rst
index 8678d5468..2200af25c 100644
--- a/docs/introduction/howtoget.rst
+++ b/docs/introduction/howtoget.rst
@@ -152,6 +152,14 @@ Install the OCaml compiler and the libraries which Tezos depends on:
 
    make build-deps
 
+Alternatively, if you want to be able to install extra packages
+(development packages such as `merlin`), you may use the following
+command instead:
+
+::
+
+   make build-dev-deps
+
 This command creates a local opam switch ``_opam`` where the right
 version of OCaml is compiled and installed (this takes a while but
 it's only done once).
@@ -174,11 +182,3 @@ Lastly you can also add Tezos binaries to your ``PATH`` variable,
 activate bash autocompletion and after reading the Disclaimer a few
 hundred times you are allowed to disable it with
 ``TEZOS_CLIENT_UNSAFE_DISABLE_DISCLAIMER=Y``.
-
-To add the default opam repository at a lower priority (for example to
-install merlin or test other opam packages), you can use the following
-command:
-
-::
-
-   opam repo add default --rank=-1
diff --git a/scripts/install_build_deps.raw.sh b/scripts/install_build_deps.raw.sh
index f150c5556..79e443b61 100755
--- a/scripts/install_build_deps.raw.sh
+++ b/scripts/install_build_deps.raw.sh
@@ -7,4 +7,10 @@ src_dir="$(dirname "$script_dir")"
 
 opams=$(find "$src_dir/vendors" "$src_dir/src" -name \*.opam -print)
 
-opam install $opams --deps-only --with-test -y --criteria="-notuptodate,-changed,-removed"
+export OPAMYES=${OPAMYES:=true}
+
+## In an ideal world, `--with-test` should be present only when using
+## `--dev`. But this would probably break the CI, so we postponed this
+## change until someone have some spare time. (@pirbo, @hnrgrgr)
+
+opam install $opams --deps-only --with-test --criteria="-notuptodate,-changed,-removed"
diff --git a/scripts/install_build_deps.sh b/scripts/install_build_deps.sh
index a576ca4b7..e4803c887 100755
--- a/scripts/install_build_deps.sh
+++ b/scripts/install_build_deps.sh
@@ -5,6 +5,12 @@ src_dir="$(dirname "$script_dir")"
 
 . "$script_dir"/version.sh
 
+if [ "$1" = "--dev" ]; then
+    dev=yes
+else
+    dev=
+fi
+
 opam repository set-url tezos --dont-select $opam_repository || \
     opam repository add tezos --dont-select $opam_repository > /dev/null 2>&1
 
@@ -21,6 +27,10 @@ fi
 
 eval $(opam env --shell=sh)
 
+if [ -n "$dev" ]; then
+    opam repository remove default > /dev/null 2>&1 || true
+fi
+
 if [ "$(ocaml -vnum)" != "$ocaml_version" ]; then
     opam install --unlock-base ocaml-base-compiler.$ocaml_version
 fi
@@ -28,3 +38,8 @@ fi
 opam list --installed opam-depext || opam --yes install opam-depext
 
 "$script_dir"/install_build_deps.raw.sh
+
+if [ -n "$dev" ]; then
+    opam repository add default --rank=-1 > /dev/null 2>&1 || true
+    opam install merlin
+fi