Tablet sales will grow 11 percent to 229 million units in 2014 against 55 percent growth in 2013, said Gartner.
The research report said tablet sales growth is slowing down in 2014 as new hardware buyers turn to alternative devices and existing users extend the lifetime of their tablets.
Tablet sales worldwide will represent 9.5 percent of total worldwide sales of devices in 2014.
The global sale of devices including PCs, tablets, ultramobiles and mobile phones will grow 3.2 percent to 2.4 billion units in 2014.
There will be over 90 million fewer new tablet purchasers and 155 million fewer tablet replacements through 2018.
Some tablet users are not replacing a tablet with a tablet, they are favoring hybrid or two-in-one devices, increasing its share of the ultramobile premium market to 22 percent in 2014, and 32 percent by 2018.
Sales of basic smartphones including midrange Android devices are projected to grow 52 percent in 2014, while utility smartphone units including low-end Chinese white box devices will double.
As smartphones reach lower prices, Gartner expects nine out of 10 phones to be smartphones by 2018.
Global market share of smartphones is set to reach 71 percent in 2014, up 17 percentage points from 2013.
Android is set to grow 47 percent in 2014. In 2015, Android devices will reach one billion in emerging markets, driven by sales of lower-cost products.