diff --git a/NEWS.md b/NEWS.md
index 20a95cdf..70d2bb5c 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,10 @@
 # reactable 0.4.1.9000 (Unreleased)
 
+## Minor improvements and bug fixes
+
+* Fixed rendering of embedded HTML widgets when `htmlwidgets` 1.6.0 or later is installed.
+  In general, fixed rendering of any Shiny HTML tags with duplicate attributes. (@tomsing1, [#306](https://github.com/glin/reactable/issues/304))
+
 # reactable 0.4.1
 
 [Documentation - reactable 0.4.1](https://v0-4-1--reactable-docs.netlify.app/)
diff --git a/R/utils.R b/R/utils.R
index 678f26f4..f19fa240 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -131,6 +131,7 @@ asReactTag <- function(x) {
   # Filter null elements for proper hydration
   x$children <- filterNulls(x$children)
   x$children <- lapply(x$children, asReactTag)
+  x <- normalizeTagAttributes(x)
   x$attribs <- asReactAttributes(x$attribs, x$name)
   x
 }
@@ -172,6 +173,18 @@ unnestTagList <- function(x) {
   htmltools::attachDependencies(tags, htmlDeps)
 }
 
+# Normalize tags that may have duplicate attributes, such as duplicate class attributes
+# in HTML widgets with htmlwidgets >= 1.6.0.
+normalizeTagAttributes <- function(tag) {
+  attribNames <- names(tag$attribs)
+  for (dupAttrib in attribNames[duplicated(attribNames)]) {
+    combinedValue <- htmltools::tagGetAttribute(tag, dupAttrib)
+    tag$attribs[attribNames == dupAttrib] <- NULL
+    tag$attribs[[dupAttrib]] <- combinedValue
+  }
+  tag
+}
+
 # Transform HTML attributes to React DOM attributes.
 # Not all attributes are supported at the moment - notable exceptions are
 # some event handler attributes and `selected` attributes for <option> elements.
diff --git a/tests/testthat/test-utils.R b/tests/testthat/test-utils.R
index 8e05e657..a83690b4 100644
--- a/tests/testthat/test-utils.R
+++ b/tests/testthat/test-utils.R
@@ -158,6 +158,14 @@ test_that("asReactTag", {
   # Attributes should be preserved
   expect_equal(asReactTag(div(factor("xy"))), div("xy"))
   expect_equal(asReactTag(div(div(as.Date("2019-01-03")))), div(div("2019-01-03")))
+
+  # Duplicate attributes should be included and collapsed (e.g., for likelihood of
+  # duplicate class attributes in HTML widgets with htmlwidgets >= 1.6.0)
+  expect_equal(asReactTag(div(class = "a", class = "b")), div(className = "a b"))
+  expect_equal(
+    asReactTag(span(class = "a", test = "t", style = list(color = "red"), class = "bb", style = list(color = "blue"))),
+    span(test = "t", style = list(list(color = "red"), list(color = "blue")), className = "a bb")
+  )
 })
 
 test_that("asReactTag preserves HTML dependencies", {