diff --git a/clients/lsp-ocaml.el b/clients/lsp-ocaml.el
index 59ffa9cb18..4d5102aac5 100644
--- a/clients/lsp-ocaml.el
+++ b/clients/lsp-ocaml.el
@@ -31,10 +31,20 @@
   :group 'lsp-mode
   :link '(url-link "https://github.com/freebroccolo/ocaml-language-server"))
 
-(define-obsolete-variable-alias
-  'lsp-ocaml-ocaml-lang-server-command
-  'lsp-ocaml-lang-server-command
-  "lsp-mode 6.1")
+(defgroup lsp-ocaml-lsp-server nil
+  "LSP support for OCaml, using ocaml-lsp-server."
+  :group 'lsp-mode
+  :link '(url-link "https://github.com/ocaml/ocaml-lsp"))
+
+;; Custom vars
+(defcustom lsp-ocaml-lsp-server-command
+  '("ocamllsp")
+  "Command to start ocaml-language-server."
+  :group 'lsp-ocaml
+  :type '(choice
+          (string :tag "Single string value")
+          (repeat :tag "List of string values"
+                  string)))
 
 (defcustom lsp-ocaml-lang-server-command
   '("ocaml-language-server" "--stdio")
@@ -45,6 +55,58 @@
           (repeat :tag "List of string values"
                   string)))
 
+(defcustom lsp-ocaml-semantic-highlighting '("full")
+  "Semantic highlighting options for ocaml-language-server.
+
+   To enable non-incremental (expectedly slower but more stable)
+   version, choose 'Full'.
+
+   To enable incremental (potentially faster but more
+   error-prone) version, choose 'Full Delta'."
+  :group 'lsp-ocaml
+  :type '(choice
+          (const :tag "Full" "full")
+          (const :tag "Full Delta" "full/delta")))
+
+(defcustom lsp-ocaml-extended-hover nil
+  "Alternative hover command providing additional information."
+  :group 'lsp-ocaml
+  :type 'boolean)
+
+(defcustom lsp-ocaml-codelens nil
+  "Enable CodeLens."
+  :group 'lsp-ocaml
+  :type 'boolean)
+
+(defcustom lsp-ocaml-dune-diagnostics t
+  "Use dune to provide diagnostics, such as mli and ml type mismatches."
+  :group 'lsp-ocaml
+  :type 'boolean)
+
+(defcustom lsp-ocaml-inlay-hints nil
+  "Enable inlay hints."
+  :group 'lsp-ocaml
+  :type 'boolean)
+
+(defcustom lsp-ocaml-syntax-documentation nil
+  "Display documentation about when hovering over OCaml code."
+  :group 'lsp-ocaml
+  :type 'boolean)
+
+(defcustom lsp-ocaml-merlin-jump-code-actions nil
+  "Allow Merlin-type code navigation in a source buffer."
+  :group 'lsp-ocaml
+  :type 'boolean)
+
+(defcustom lsp-ocaml-trace-server "off"
+  "Enable tracing of the server communication."
+  :group 'lsp-ocaml
+  :type '(choice
+          (const :tag "Off" "off")
+          (const :tag "Compact" "compact")
+          (const :tag "Messages" "messages")
+          (const :tag "Verbose" "verbose")))
+
 (lsp-register-client
  (make-lsp-client :new-connection (lsp-stdio-connection
                                    (lambda () lsp-ocaml-lang-server-command))
@@ -52,22 +114,28 @@
                   :priority -1
                   :server-id 'ocaml-ls))
 
-(defgroup lsp-ocaml-lsp-server nil
-  "LSP support for OCaml, using ocaml-lsp-server."
-  :group 'lsp-mode
-  :link '(url-link "https://github.com/ocaml/ocaml-lsp"))
 
+;; Obsolete aliases
+(define-obsolete-variable-alias
+  'lsp-ocaml-ocaml-lang-server-command
+  'lsp-ocaml-lang-server-command
+  "lsp-mode 6.1")
 (define-obsolete-variable-alias 'lsp-merlin 'lsp-ocaml-lsp-server "lsp-mode 6.1")
 (define-obsolete-variable-alias 'lsp-merlin-command 'lsp-ocaml-lsp-server-command "lsp-mode 6.1")
 
-(defcustom lsp-ocaml-lsp-server-command
-  '("ocamllsp")
-  "Command to start ocaml-language-server."
-  :group 'lsp-ocaml
-  :type '(choice
-          (string :tag "Single string value")
-          (repeat :tag "List of string values"
-                  string)))
+
+;; TODO most of these need some sort of command implementation
+(defun lsp-ocaml--make-custom-settings ()
+  "Return custom settings for ocaml-language-server."
+  (list
+   :extendedHover (list :enable lsp-ocaml-extended-hover)
+   :codelens (list :enable lsp-ocaml-codelens)
+   :duneDiagnostics (list :enable lsp-ocaml-dune-diagnostics)
+   :inlayHints (list :enable lsp-ocaml-inlay-hints)
+   :syntaxDocumentation (list :enable lsp-ocaml-syntax-documentation)
+   :merlinJumpCodeActions (list :enable lsp-ocaml-merlin-jump-code-actions)
+   :trace (list :server lsp-ocaml-trace-server)
+   :extendedHover (list :enable lsp-ocaml-extended-hover)))
 
 (lsp-register-client
  (make-lsp-client
@@ -75,13 +143,16 @@
   (lsp-stdio-connection (lambda () lsp-ocaml-lsp-server-command))
   :major-modes '(reason-mode caml-mode tuareg-mode)
   :priority 0
+  :environment-fn (lambda ()
+                    '(("OCAMLLSP_SEMANTIC_HIGHLIGHTING" . lsp-ocaml-semantic-highlighting)))
+  :initialization-options 'lsp-ocaml--make-custom-settings
   :server-id 'ocaml-lsp-server))
 
 (defcustom lsp-cut-signature 'space
   "If non-nil, signatures returned on hover will not be split on newline."
   :group 'lsp-ocaml
   :type '(choice (symbol :tag "Default behaviour" 'cut)
-                 (symbol :tag "Display all the lines with spaces" 'space)))
+          (symbol :tag "Display all the lines with spaces" 'space)))
 
 (cl-defmethod lsp-clients-extract-signature-on-hover (contents (_server-id (eql ocaml-lsp-server)) &optional storable)
   "Extract a representative line from OCaml's CONTENTS, to show in the echo area.