diff --git a/DESCRIPTION b/DESCRIPTION
index f16a46112..e69c40e88 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -112,6 +112,7 @@ Collate:
     'ifelse_censor_linter.R'
     'implicit_assignment_linter.R'
     'implicit_integer_linter.R'
+    'in_linter.R'
     'indentation_linter.R'
     'infix_spaces_linter.R'
     'inner_combine_linter.R'
diff --git a/NAMESPACE b/NAMESPACE
index 1b2702104..5eb2897fa 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -78,6 +78,7 @@ export(if_switch_linter)
 export(ifelse_censor_linter)
 export(implicit_assignment_linter)
 export(implicit_integer_linter)
+export(in_linter)
 export(indentation_linter)
 export(infix_spaces_linter)
 export(inner_combine_linter)
diff --git a/R/in_linter.R b/R/in_linter.R
new file mode 100644
index 000000000..cc4ac1d63
--- /dev/null
+++ b/R/in_linter.R
@@ -0,0 +1,35 @@
+#' Chained equality check linter
+#'
+#' Report the use of chained equality checks where `%in%` would be more
+#' appropriate
+#'
+#' @examples
+#' # lints
+#' lint(
+#'   text = "x == 'a' | x == 'b'",
+#'   linters = in_linter()
+#' )
+#'
+#' # This only makes sense in the case x if of length 1
+#' lint(
+#'   text = "x == 'a' || x == 'b'",
+#'   linters = in_linter()
+#' )
+#'
+#' # okay
+#' lint(
+#'   text = "x %in% c('a', 'b')",
+#'   linters = in_linter()
+#' )
+#'
+#' @evalRd rd_tags("in_linter")
+#' @seealso [linters] for a complete list of linters available in lintr.
+#' @export
+in_linter <- make_linter_from_xpath(
+  xpath = "(//OR|//OR2)[
+    preceding-sibling::expr[EQ]
+    and following-sibling::expr[EQ]
+    and preceding-sibling::expr/expr/SYMBOL/text() = following-sibling::expr/expr/SYMBOL/text()
+  ]",
+  lint_message = "Use %in% to test equality of a variable against multiple values."
+)
diff --git a/inst/lintr/linters.csv b/inst/lintr/linters.csv
index 95af98b61..5a5f55310 100644
--- a/inst/lintr/linters.csv
+++ b/inst/lintr/linters.csv
@@ -42,6 +42,7 @@ if_switch_linter,best_practices readability consistency efficiency configurable
 ifelse_censor_linter,best_practices efficiency
 implicit_assignment_linter,style best_practices readability configurable
 implicit_integer_linter,style consistency best_practices configurable
+in_linter,readability efficiency best_practices
 indentation_linter,style readability default configurable
 infix_spaces_linter,style readability default configurable
 inner_combine_linter,efficiency consistency readability
diff --git a/man/best_practices_linters.Rd b/man/best_practices_linters.Rd
index 9e55cb99e..7d3889b4f 100644
--- a/man/best_practices_linters.Rd
+++ b/man/best_practices_linters.Rd
@@ -40,6 +40,7 @@ The following linters are tagged with 'best_practices':
 \item{\code{\link{ifelse_censor_linter}}}
 \item{\code{\link{implicit_assignment_linter}}}
 \item{\code{\link{implicit_integer_linter}}}
+\item{\code{\link{in_linter}}}
 \item{\code{\link{is_numeric_linter}}}
 \item{\code{\link{length_levels_linter}}}
 \item{\code{\link{lengths_linter}}}
diff --git a/man/efficiency_linters.Rd b/man/efficiency_linters.Rd
index 37cb8b0d7..d5df5260f 100644
--- a/man/efficiency_linters.Rd
+++ b/man/efficiency_linters.Rd
@@ -19,6 +19,7 @@ The following linters are tagged with 'efficiency':
 \item{\code{\link{fixed_regex_linter}}}
 \item{\code{\link{if_switch_linter}}}
 \item{\code{\link{ifelse_censor_linter}}}
+\item{\code{\link{in_linter}}}
 \item{\code{\link{inner_combine_linter}}}
 \item{\code{\link{length_test_linter}}}
 \item{\code{\link{lengths_linter}}}
diff --git a/man/in_linter.Rd b/man/in_linter.Rd
new file mode 100644
index 000000000..e4f6281ac
--- /dev/null
+++ b/man/in_linter.Rd
@@ -0,0 +1,38 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/in_linter.R
+\name{in_linter}
+\alias{in_linter}
+\title{Chained equality check linter}
+\usage{
+in_linter()
+}
+\description{
+Report the use of chained equality checks where \code{\%in\%} would be more
+appropriate
+}
+\examples{
+# lints
+lint(
+  text = "x == 'a' | x == 'b'",
+  linters = in_linter()
+)
+
+# This only makes sense in the case x if of length 1
+lint(
+  text = "x == 'a' || x == 'b'",
+  linters = in_linter()
+)
+
+# okay
+lint(
+  text = "x \%in\% c('a', 'b')",
+  linters = in_linter()
+)
+
+}
+\seealso{
+\link{linters} for a complete list of linters available in lintr.
+}
+\section{Tags}{
+\link[=best_practices_linters]{best_practices}, \link[=efficiency_linters]{efficiency}, \link[=readability_linters]{readability}
+}
diff --git a/man/linters.Rd b/man/linters.Rd
index 394bd6126..affd21d7f 100644
--- a/man/linters.Rd
+++ b/man/linters.Rd
@@ -17,18 +17,18 @@ see also \code{\link[=available_tags]{available_tags()}}.
 \section{Tags}{
 The following tags exist:
 \itemize{
-\item{\link[=best_practices_linters]{best_practices} (63 linters)}
+\item{\link[=best_practices_linters]{best_practices} (64 linters)}
 \item{\link[=common_mistakes_linters]{common_mistakes} (11 linters)}
 \item{\link[=configurable_linters]{configurable} (44 linters)}
 \item{\link[=consistency_linters]{consistency} (32 linters)}
 \item{\link[=correctness_linters]{correctness} (7 linters)}
 \item{\link[=default_linters]{default} (25 linters)}
 \item{\link[=deprecated_linters]{deprecated} (6 linters)}
-\item{\link[=efficiency_linters]{efficiency} (32 linters)}
+\item{\link[=efficiency_linters]{efficiency} (33 linters)}
 \item{\link[=executing_linters]{executing} (6 linters)}
 \item{\link[=package_development_linters]{package_development} (14 linters)}
 \item{\link[=pkg_testthat_linters]{pkg_testthat} (12 linters)}
-\item{\link[=readability_linters]{readability} (64 linters)}
+\item{\link[=readability_linters]{readability} (65 linters)}
 \item{\link[=regex_linters]{regex} (4 linters)}
 \item{\link[=robustness_linters]{robustness} (17 linters)}
 \item{\link[=style_linters]{style} (40 linters)}
@@ -78,6 +78,7 @@ The following linters exist:
 \item{\code{\link{ifelse_censor_linter}} (tags: best_practices, efficiency)}
 \item{\code{\link{implicit_assignment_linter}} (tags: best_practices, configurable, readability, style)}
 \item{\code{\link{implicit_integer_linter}} (tags: best_practices, configurable, consistency, style)}
+\item{\code{\link{in_linter}} (tags: best_practices, efficiency, readability)}
 \item{\code{\link{indentation_linter}} (tags: configurable, default, readability, style)}
 \item{\code{\link{infix_spaces_linter}} (tags: configurable, default, readability, style)}
 \item{\code{\link{inner_combine_linter}} (tags: consistency, efficiency, readability)}
diff --git a/man/readability_linters.Rd b/man/readability_linters.Rd
index 372d2fd9e..6f16b965d 100644
--- a/man/readability_linters.Rd
+++ b/man/readability_linters.Rd
@@ -33,6 +33,7 @@ The following linters are tagged with 'readability':
 \item{\code{\link{if_not_else_linter}}}
 \item{\code{\link{if_switch_linter}}}
 \item{\code{\link{implicit_assignment_linter}}}
+\item{\code{\link{in_linter}}}
 \item{\code{\link{indentation_linter}}}
 \item{\code{\link{infix_spaces_linter}}}
 \item{\code{\link{inner_combine_linter}}}
diff --git a/tests/testthat/test-in_linter.R b/tests/testthat/test-in_linter.R
new file mode 100644
index 000000000..87be6b507
--- /dev/null
+++ b/tests/testthat/test-in_linter.R
@@ -0,0 +1,54 @@
+test_that("in_linter catches unnecessary OR chains", {
+  linter <- in_linter()
+  lint_msg <- rex::rex("%in%")
+
+  expect_lint(
+    "x == 'a' | x == 'b'",
+    lint_msg,
+    linter
+  )
+
+  # Works with short-circuit operator
+  expect_lint(
+    "x == 'a' || x == 'b'",
+    lint_msg,
+    linter
+  )
+
+  # Works with yoda tests
+  expect_lint(
+    "'a' == x || 'b' == x",
+    lint_msg,
+    linter
+  )
+
+  # Works with 'semi-yoda' tests
+  expect_lint(
+    "x == 'a' || 'b' == x",
+    lint_msg,
+    linter
+  )
+
+  # Works with longer chains
+  expect_lint(
+    "x == 'a' | x == 'b' | x == 'c'",
+    lint_msg,
+    linter
+  )
+})
+
+test_that("common in_linter negative cases", {
+  linter <- in_linter()
+
+  expect_lint(
+    "x == 'a' | y == 'b'",
+    NULL,
+    linter
+  )
+
+  expect_lint(
+    "x == 'a' || y == 'b'",
+    NULL,
+    linter
+  )
+})