The market fell 1 percent in 2009, the first decline in eight years as consumers cut spending amid recession.
But Gartner analyst Carolina Milanesi said she now expects the market to grow 11-13 percent this year, compared with the firm's December forecast for a 9-percent increase.
The economy seems to be stabilizing more into a recovery trend than we forecast back in December, Milanesi said.
Sales will return to low-double-digit growth, but competition will continue to put a strain on vendors' margins.
Gartner is more optimistic than the top cellphone maker Nokia, which has forecast growth around 10 percent, and also slightly ahead of analysts consensus of 11 percent in a Reuters poll this month.
Gartner sees smartphone market volume growing a whopping 46 percent from 172.4 million sold last year, boosted by cheaper models. The most affordable now cost just over $100 excluding operator subsidies.
Gartner said it expects average sale prices in 2010 to fall more slowly than last year -- when intense competition hurt pricing in markets such as China and India -- helped by an improving economy and consumers upgrading to cheap smartphones.
NOKIA H1 TOUGH
Industry leader Nokia saw its market share slip last year to 36.4 percent from 38.6 percent a year before, and the research firm said more challenges lay ahead.
Nokia will face a tough first half of 2010 as improvements to Symbian and new products based on the Meego platform will not reach the market before the second half of 2010, Milanesi said.
Its very strong mid-tier portfolio will help it hold market share, but its ongoing weakness at the high end of the portfolio will hurt its share of market value, she said.
Korean vendors Samsung Electronics and LG Electronics gained handset market share last year, up to 19.5 percent and 10.1 percent respectively.
BlackBerry-maker Research in Motion and Apple controlled 19.9 percent and 14.4 percent of the smartphone market in 2010, but both lost some share in the fourth quarter to phones with Google's Android software.
All vendors in total sold 6.8 million Android phones last year, giving it a 3.9 percent share of the smartphone market, compared with just 0.5 percent a year before.
Gartner said Android's success should continue into 2010 as more manufacturers launch Android phones, but noted some manufacturers have expressed growing concern about Google's intentions in the mobile market.
If such concerns cause manufacturers to change their product strategies or operators to change which devices they stock, this might hinder Android's growth in 2010, Gartner said.
(Editing by David Cowell)