diff --git a/library/data/vector.lean b/library/data/vector.lean
index c7827f44e7..f975f42ae5 100644
--- a/library/data/vector.lean
+++ b/library/data/vector.lean
@@ -35,7 +35,7 @@ namespace vec
         (λa, inhabited.destruct iH
           (λv, inhabited.mk (vec.cons a v))))
 
-  theorem case_zero_lem [private] {C : vec T 0 → Type} {n : ℕ} (v : vec T n) (Hnil : C nil) :
+  private theorem case_zero_lem {C : vec T 0 → Type} {n : ℕ} (v : vec T n) (Hnil : C nil) :
     ∀ H : n = 0, C (cast (congr_arg (vec T) H) v) :=
   rec_on v (take H : 0 = 0, (eq.rec Hnil (cast_eq _ nil⁻¹)))
   (take (x : T) (n : ℕ) (w : vec T n) IH (H : succ n = 0),
@@ -44,7 +44,7 @@ namespace vec
   theorem case_zero {C : vec T 0 → Type} (v : vec T 0) (Hnil : C nil) : C v :=
   eq.rec (case_zero_lem v Hnil (eq.refl 0)) (cast_eq _ v)
 
-  theorem rec_nonempty_lem [private] {C : Π{n}, vec T (succ n) → Type} {n : ℕ} (v : vec T n)
+  private theorem rec_nonempty_lem {C : Π{n}, vec T (succ n) → Type} {n : ℕ} (v : vec T n)
     (Hone : Πa, C [a]) (Hcons : Πa {n} (v : vec T (succ n)), C v → C (a :: v))
     : ∀{m} (H : n = succ m), C (cast (congr_arg (vec T) H) v) :=
   case_on v (take m (H : 0 = succ m), false.rec_type _ (absurd (H⁻¹) succ_ne_zero))
@@ -62,7 +62,7 @@ namespace vec
     (Hone : Πa, C [a]) (Hcons : Πa {n} (v : vec T (succ n)), C v → C (a :: v)) : C v :=
   sorry
 
-  theorem case_succ_lem [private] {C : Π{n}, vec T (succ n) → Type} {n : ℕ} (v : vec T n)
+  private theorem case_succ_lem {C : Π{n}, vec T (succ n) → Type} {n : ℕ} (v : vec T n)
     (H : Πa {n} (v : vec T n), C (a :: v))
     : ∀{m} (H : n = succ m), C (cast (congr_arg (vec T) H) v) :=
   sorry
diff --git a/library/logic/axioms/examples/diaconescu.lean b/library/logic/axioms/examples/diaconescu.lean
index a894487582..0ff9e03141 100644
--- a/library/logic/axioms/examples/diaconescu.lean
+++ b/library/logic/axioms/examples/diaconescu.lean
@@ -13,17 +13,17 @@ hypothesis propext {a b : Prop} : (a → b) → (b → a) → a = b
 
 parameter p : Prop
 
-definition u [private] := epsilon (λx, x = true ∨ p)
+private definition u := epsilon (λx, x = true ∨ p)
 
-definition v [private] := epsilon (λx, x = false ∨ p)
+private definition v := epsilon (λx, x = false ∨ p)
 
-lemma u_def [private] : u = true ∨ p :=
+private lemma u_def : u = true ∨ p :=
 epsilon_spec (exists_intro true (or.inl rfl))
 
-lemma v_def [private] : v = false ∨ p :=
+private lemma v_def : v = false ∨ p :=
 epsilon_spec (exists_intro false (or.inl rfl))
 
-lemma uv_implies_p [private] : ¬(u = v) ∨ p :=
+private lemma uv_implies_p : ¬(u = v) ∨ p :=
 or.elim u_def
   (assume Hut : u = true, or.elim v_def
     (assume Hvf : v = false,
@@ -32,7 +32,7 @@ or.elim u_def
     (assume Hp : p, or.inr Hp))
   (assume Hp : p, or.inr Hp)
 
-lemma p_implies_uv [private] : p → u = v :=
+private lemma p_implies_uv : p → u = v :=
 assume Hp : p,
   have Hpred : (λ x, x = true ∨ p) = (λ x, x = false ∨ p), from
     funext (take x : Prop,
diff --git a/src/emacs/lean-syntax.el b/src/emacs/lean-syntax.el
index 75fabae22b..8280d323ae 100644
--- a/src/emacs/lean-syntax.el
+++ b/src/emacs/lean-syntax.el
@@ -8,13 +8,13 @@
 (require 'rx)
 
 (defconst lean-keywords
-  '("import" "reducible" "tactic_hint" "opaque" "definition" "renaming"
+  '("import" "reducible" "tactic_hint" "private" "opaque" "definition" "renaming"
     "inline" "hiding" "exposing" "parameter" "parameters" "begin" "proof" "qed" "conjecture"
     "hypothesis" "lemma" "corollary" "variable" "variables" "print" "theorem"
     "context" "open" "as" "export" "axiom" "inductive" "with" "structure" "universe" "alias" "help" "environment"
     "options" "precedence" "postfix" "prefix" "calc_trans" "calc_subst" "calc_refl"
     "infix" "infixl" "infixr" "notation" "eval" "check" "exit" "coercion" "end"
-    "private" "using" "namespace" "builtin" "including" "instance" "class" "section"
+    "using" "namespace" "builtin" "including" "instance" "class" "section"
     "set_option" "add_rewrite" "extends")
   "lean keywords")
 
@@ -70,7 +70,7 @@
      ;; place holder
      (,(rx symbol-start "_" symbol-end) . 'font-lock-preprocessor-face)
      ;; modifiers
-     (,(rx (or "\[persistent\]" "\[notation\]" "\[visible\]" "\[protected\]" "\[private\]"
+     (,(rx (or "\[persistent\]" "\[notation\]" "\[visible\]" "\[protected\]"
                "\[instance\]" "\[class\]" "\[coercion\]" "\[off\]" "\[none\]" "\[on\]")) . 'font-lock-doc-face)
      ;; tactics
      (,(rx symbol-start
diff --git a/src/frontends/lean/decl_cmds.cpp b/src/frontends/lean/decl_cmds.cpp
index 8992f45695..d4d2e9c8ac 100644
--- a/src/frontends/lean/decl_cmds.cpp
+++ b/src/frontends/lean/decl_cmds.cpp
@@ -27,7 +27,7 @@ static name g_rcurly("}");
 static name g_colon(":");
 static name g_assign(":=");
 static name g_definition("definition");
-static name g_private("[private]");
+static name g_theorem("theorem");
 static name g_protected("[protected]");
 static name g_instance("[instance]");
 static name g_coercion("[coercion]");
@@ -162,13 +162,11 @@ environment axiom_cmd(parser & p)    {
 }
 
 struct decl_modifiers {
-    bool m_is_private;
     bool m_is_protected;
     bool m_is_instance;
     bool m_is_coercion;
     bool m_is_reducible;
     decl_modifiers() {
-        m_is_private   = false;
         m_is_protected = false;
         m_is_instance  = false;
         m_is_coercion  = false;
@@ -177,10 +175,7 @@ struct decl_modifiers {
 
     void parse(parser & p) {
         while (true) {
-            if (p.curr_is_token(g_private)) {
-                m_is_private = true;
-                p.next();
-            } else if (p.curr_is_token(g_protected)) {
+            if (p.curr_is_token(g_protected)) {
                 m_is_protected = true;
                 p.next();
             } else if (p.curr_is_token(g_instance)) {
@@ -209,7 +204,7 @@ static void erase_local_binder_info(buffer<expr> & ps) {
         p = update_local(p, binder_info());
 }
 
-environment definition_cmd_core(parser & p, bool is_theorem, bool is_opaque) {
+environment definition_cmd_core(parser & p, bool is_theorem, bool is_opaque, bool is_private) {
     auto n_pos = p.pos();
     unsigned start_line = n_pos.first;
     name n     = p.check_id_next("invalid declaration, identifier expected");
@@ -278,7 +273,7 @@ environment definition_cmd_core(parser & p, bool is_theorem, bool is_opaque) {
         p.declare_sorry();
     environment env = p.env();
 
-    if (modifiers.m_is_private) {
+    if (is_private) {
         auto env_n = add_private_name(env, n, optional<unsigned>(hash(p.pos().first, p.pos().second)));
         env    = env_n.first;
         real_n = env_n.second;
@@ -316,7 +311,7 @@ environment definition_cmd_core(parser & p, bool is_theorem, bool is_opaque) {
                     cd = check(env, mk_theorem(real_n, c_ls, c_type, c_value));
                 else
                     cd = check(env, mk_definition(env, real_n, c_ls, c_type, c_value, is_opaque));
-                if (!modifiers.m_is_private)
+                if (!is_private)
                     p.add_decl_index(real_n, n_pos, p.get_cmd_token(), c_type);
                 env = module::add(env, *cd);
                 found_cached = true;
@@ -348,7 +343,7 @@ environment definition_cmd_core(parser & p, bool is_theorem, bool is_opaque) {
             env = module::add(env, check(env, mk_definition(env, real_n, new_ls, type, value, is_opaque)));
             p.cache_definition(real_n, pre_type, pre_value, new_ls, type, value);
         }
-        if (!modifiers.m_is_private)
+        if (!is_private)
             p.add_decl_index(real_n, n_pos, p.get_cmd_token(), type);
     }
 
@@ -365,14 +360,26 @@ environment definition_cmd_core(parser & p, bool is_theorem, bool is_opaque) {
     return env;
 }
 environment definition_cmd(parser & p) {
-    return definition_cmd_core(p, false, false);
+    return definition_cmd_core(p, false, false, false);
 }
 environment opaque_definition_cmd(parser & p) {
     p.check_token_next(g_definition, "invalid 'opaque' definition, 'definition' expected");
-    return definition_cmd_core(p, false, true);
+    return definition_cmd_core(p, false, true, false);
 }
 environment theorem_cmd(parser & p) {
-    return definition_cmd_core(p, true, true);
+    return definition_cmd_core(p, true, true, false);
+}
+environment private_definition_cmd(parser & p) {
+    bool is_theorem = false;
+    if (p.curr_is_token_or_id(g_definition)) {
+        p.next();
+    } else if (p.curr_is_token_or_id(g_theorem)) {
+        p.next();
+        is_theorem = true;
+    } else {
+        throw parser_error("invalid 'private' definition/theorem, 'definition' or 'theorem' expected", p.pos());
+    }
+    return definition_cmd_core(p, is_theorem, true, true);
 }
 
 static name g_lparen("("), g_lcurly("{"), g_ldcurly("⦃"), g_lbracket("[");
@@ -418,6 +425,7 @@ void register_decl_cmds(cmd_table & r) {
     add_cmd(r, cmd_info("axiom",        "declare a new axiom", axiom_cmd));
     add_cmd(r, cmd_info("definition",   "add new definition", definition_cmd));
     add_cmd(r, cmd_info("opaque",       "add new opaque definition", opaque_definition_cmd));
+    add_cmd(r, cmd_info("private",      "add new private definition/theorem", private_definition_cmd));
     add_cmd(r, cmd_info("theorem",      "add new theorem", theorem_cmd));
     add_cmd(r, cmd_info("variables",    "declare new parameters", variables_cmd));
 }
diff --git a/src/frontends/lean/token_table.cpp b/src/frontends/lean/token_table.cpp
index 502ccea63f..92f9a229d8 100644
--- a/src/frontends/lean/token_table.cpp
+++ b/src/frontends/lean/token_table.cpp
@@ -77,8 +77,8 @@ token_table init_token_table() {
          {"(*", 0}, {"/-", 0}, {"begin", g_max_prec}, {"proof", g_max_prec}, {"qed", 0}, {"@", g_max_prec}, {"including", 0}, {"sorry", g_max_prec},
          {"+", g_plus_prec}, {g_cup, g_cup_prec}, {"->", g_arrow_prec}, {nullptr, 0}};
 
-    char const * commands[] = {"theorem", "axiom", "variable", "opaque", "definition", "coercion",
-                               "variables", "[persistent]", "[private]", "[protected]", "[visible]", "[instance]",
+    char const * commands[] = {"theorem", "axiom", "variable", "private", "opaque", "definition", "coercion",
+                               "variables", "[persistent]", "[protected]", "[visible]", "[instance]",
                                "[off]", "[on]", "[none]", "[class]", "[coercion]", "[reducible]", "reducible",
                                "evaluate", "check", "print", "end", "namespace", "section", "import",
                                "inductive", "record", "renaming", "extends", "structure", "module", "universe",
diff --git a/tests/lean/t5.lean b/tests/lean/t5.lean
index e5a96a17c9..fcaf337c24 100644
--- a/tests/lean/t5.lean
+++ b/tests/lean/t5.lean
@@ -6,7 +6,7 @@ check g
 namespace foo
   definition h : N := f a
   check h
-  definition q [private] : N := f a
+  private definition q : N := f a
   check q
 end foo
 check foo.h
diff --git a/tests/lean/t7.lean b/tests/lean/t7.lean
index 972b28f629..4de279db5b 100644
--- a/tests/lean/t7.lean
+++ b/tests/lean/t7.lean
@@ -5,7 +5,7 @@ section
   parameter   R : A → A → Prop
   parameter   B : Type
   definition  id (a : A) : A := a
-  definition  refl [private] : Prop := ∀ (a : A), R a a
+  private definition  refl : Prop := ∀ (a : A), R a a
   definition  symm : Prop := ∀ (a b : A), R a b → R b a
   definition  trans : Prop := ∀ (a b c : A), R a b → R b c → R a c
   definition  equivalence : Prop := and (and refl symm) trans