The strong Lyman alpha emission from galaxies acts as a beacon for identifying high-redshift galaxies. Galaxies selected using the narrow-band imaging of this emission line (i.e., Lyman Alpha Emitters, or LAEs) are typically young, low-mass galaxies in the early stages of galaxy formation and may be the basic galactic building blocks in hierarchical galaxy formation theories. LAEs can therefore be used to probe the low-mass end of the galaxy mass function at high redshifts. We present HST/WFC3 imaging of a sample of spectroscopically confirmed LAE candidates at z ~ 2.65. We observed LAEs selected from the Bootes field of the NOAO Deep Wide-Field Survey through the WFC3 F110W (J), F160W (H) and F139M filters. The J and H filters span the redshifted age-sensitive Balmer break region and the F139M samples the spectral region containing the [OII] emission line at z ~ 2.65. We combine the HST data with ground based photometry, fit the resulting spectral energy distribution and estimate the stellar mass, age, star formation rate and dust extinction for each LAE. We find that the bulk of sources are young (< 300 Myr), low mass (< 109 Msun) and compact, similar to local star-forming dwarf galaxies like the Magellanic Clouds. We present results on the [OII] emission line properties of the LAEs and compare the properties of these sub-L* galaxies with their more massive counterparts at similar redshift.